The review of advances in the field of the development of light-sensitive recording media for archival and working optical memory with a high information capacity is presented. The prospects for making angular- and frequency- selective as well as two-photon optical memories based on organic and inorganic recording media are discussed.

Erasable holographic information storage plays an important role in optical data storage. In this review, a description of the photochromism observed in Spiropyran doped polymer materials is given, with the observed results on erasable holography. A discussion of holographic information storage is also made.

Optical and holographic properties of bacteriorhodopsin recording materials are considered. The use of short light pulses for recording in BR materials is shown to lead to a decrease in their sensitivity and diffraction efficiency. The relationship between BR properties and the write pulse width is shown to depend on the photosensitivity of BR short-living forms.

The investigations of hologram recording on a basis of photochemical polymerization reaction in polymer films have lead to creation the number of new holographic materials13. It is expected that their application will be realized in the nearest future. The performances of holographic recording useful for practice, such as sensitivity, maximum of diffraction efficiency (DE), storage, spatial resolution and other have been investigated in detail for this films4'5. But the question of mechanism of hologram formation, including the description of kinetic of photochemical and chemical stages of hologram recording is keeping open and discussed5'6. The holographic performances of HPPM-633 which consist of the light absorbing dye (Methylene Blue), initiator (triethanolamine - TEA), monomer (acrylamide -M), cross-linking monomer (hexamethylenbisacrylamide) and polymer binder (polyvinylalcohol) at He-Ne laser continuous recording were described7'8. In the preliminary investigation of hologram recording in HPPM-633 by the He-Ne laser pulses it was established that the DE about 1-5% appear at exposition time 0, 1 s with laser beam power density 0,05-0,1 W/cm2. The Fig. 1 illustrates the pulse hologram growth curves in HPPM633 , The phenomenon of hologram dark amplification (see Fig.2a,b) was observed in this experiment , That fact is in accordance with the mechanism of free-radical polymerization in HPPM. In this case the monomer polymerization in plasticizered polymer may expand independently after initial laser pulse action. It is interesting to know in which way the polymerization accrues at earlier stages. But the employment of pulse setup on the base of He-Ne laser does not allow to investigate the dark processes at time less then 0. 1 sec. To elucidate the material behaviour at the initial stages of the polymerization process immediately after excitation of the absorbing dye to the triplet state it is necessary to record the diffraction grating by laser pulse with durability about 108 sec. The DE growth of hologram under these conditions fall into nonsteady-state case of the polymerization. Thus we must to connect the hologram DE temporal dependence (DE(t)) with kinetic model of polymerization reactions in nonsteady-state case to have a possibility of the chemical interpretation of the obtained experimental date.

The development and progress of many optical techniques including dynamical holography, real-time optical information processing and degenerate four-wave mixing are strongly dependent on new optical recording materials. So we present, in this paper, new and complementary characterization results of two recording materials usable for industrial applications: 1 degree(s) dye doped colloids solid films, 2 degree(s) azoic-dye doped colloids thin solid films. Those optical materials are simple to prepare and use for scientific and industrial applications. Because they are self-processing (no post-exposure chemical or thermal processing is needed) they can be used in many real-time applications.

The properties and mechanism of relaxation processes of holographic gratings in amorphous chalcogenide semiconductor films have been studied. The possibilities of the practical applications of these materials as the photoresists for the production of the relief holograms and holographic optical elements are discussed. It is shown that the self- enhancement phenomenon of holographic recording in amorphous chalcogenide semiconductor films by light or thermal treatment can be used to increase the diffraction efficiency of the holograms.

The photocycle of the 4-keto bacteriorhodopsin is investigated. We constructed a multilevel theoretical model for the transmittance properties of the material. Adjusting the relaxation parameters we are able to fit the theoretical intensity dependent transmittance curves into the experiments. Thus we determine the photocycle from simple optical measurements. This method provides a new approach for studying light-induced changes in photochromic proteins.

The change of the dark relaxation rate of the bacteriorhodopsin (BR) hologram diffraction efficiency with write pulse width is considered. The heating of the BR film with light pulses is shown to be the cause. The effect of thermal exposure can be reduced by increasing the hologram spatial frequency.

Analysis has been made of the effect of the recording process parameters on formation dynamics and microstructure of relief-phase holograms recorded on photothermoplastic media by using IR radiation of a YAG:Nd³⁺-laser. Conditions has been found under which there occurs the effect of positive feedback with microrelief development process which leads to the `self-enhancement' of the relief- phase holograms. It is found that by proper selection of the development unit scheme and laser irradiation conditions the expansion of the effective spatial frequency band of about 150 - 200 mm^-1 can be achieved.

The theoretical and experimental investigations of electric field selectivity of reflection volume holograms in the geometry of the transverse electrooptic effect in LiNbO₃ are presented. The optimal configuration for the electric field selectivity has been found. The factors limiting electric field multiplexing have been analyzed.

The influence of circular dichroism on diffraction efficiency of the holograms recorded in a cubic photorefractive optically active piezocrystals is investigated. It is shown, that the account of circular dichroism allows to change values of orientation angle at which linear polarization is reached.

Photoluminescent spectra of CaO, MgO oxides, doped with rare-earth ions have been studied. The stimulated by IR- light photoluminescence in these materials has discovered at room temperature for the first time. Optically stimulated luminescence in Ca(Mg)O: Eu, Sm for different concentrations of dopants after exposure to UV-radiation ((lambda) equals 250 nm) and radiation with (lambda) equals 488 nm has been investigated. The physical model to explain luminescence and stimulated luminescence mechanism is proposed. Materials on the base of alkaline-earth oxides activated by rare-earth ions are suitable for multiple rewrite of information.

New type of high-photosensitive (10 - 160 ISO) Photo Thermoplastic matrix information carrier as `semiconductor- thermoplastic' having an intrinsic raster of 200 - 600 mm^-1 and an intrinsic thermodeveloping element is created. For the registration of low-contrast high-resolved halftone images (optical contrast is 0.002 - 0.2), a physical recording mechanism is discussed. A perspectives of application, particularly for aerospace and astrophysics recording, are considered.

The films of polymer dispersed cholesteric liquid crystals with great hysteresis of volt-contrast characteristic are a perspective media to thermooptical information recording. Thermooptical effect in this case is due to writing light absorption in the films doped by the dichroic dye. Operation characteristics of recording process, the possibility to increase the speed and resolution of laser addressed information recording have been studied.

Collective character of molecular interaction in liquid crystals creates an intrinsic feedback mechanism. Two co- propagating noncoherent beams of orthogonal polarization produce strong molecular orientation switching and optical bistability without additional external fields and feedback. The angular momentum of the combined light is easily controlled, and a light-driven molecular motor is demonstrated.

The surface of a heavy hydrocarbon liquid film is deformed due to inhomogeneous heating with a Gaussian laser beam. The surface profile and the liquid velocity distribution are calculated as functions of time. The liquid surface behaves as an aspherical mirror whose focal properties are controlled by varying the laser beam intensity. This phenomenon allows obtention of self and cross correlations of low-power laser beams. Optical properties and applications of this laser-controlled adaptive mirror are discussed.

The publication describes optical information recording process based on the photochemical etching of the aluminum films using sandwich-type structures: substrate/aluminum film/polymer light-sensitive layer. The etchers are produced during the illumination of the light-sensitive polymer layers. Processes of the etching have a high light- sensitivity due to additional post-exposure autocatalytic accumulation of the etchers.

The structural, magnetic and magneto-optical properties of Mn/RE/Bi (RE equals Nd, Eu, Cd, Tb, Dy) films prepared by multilayer technology are reported. The results of the investigations show that these films exhibit a smaller crystallite size, an improved squareness of the hysteresis loops, an enhanced Kerr rotation and a higher stability of the structural and magnetic properties than that of MnBi films. It is assumed that the specific influence of RE spacer layers on the structure is related with their atomic radius. The possible reasons of the Kerr effect enhancement in Mn/RE/Bi films were discussed: the increased matrix elements of the 6p-3d transitions, the significant polarization of Bi 6p band, the change of the density of states near the Fermi level. It was found that Mn/Dy/Bi films have best parameters: average crystallite size 15 nm, H_c equals 6 kOe, K_u equals 1 (DOT) 10⁷ erg/cc, 2(Theta) _k equals 4.5 degree(s), (Theta) _k(root)R equals 1.5 degree(s) at (lambda) equals 633 nm. The wavelength dependent of Kerr rotation have the maximum in the region (lambda) equals 633 nm that represents the practical interest. The suitable properties of Mn/Dy/Bi films allow it to use it as a magneto-optical storage medium. The results of the thermomagnetic writing and magneto-optical readout in these films were presented.

The polycrystalline cobalt ferrite films were deposited by dc-sputtering method from ferrite targets. These targets were conductive because of using of reduction atmosphere for time its preparation that allowed dc-sputtering. The magnetic and magneto-optical properties of these films have been investigated. The prepared Co_0.07Fe_2.3O₄ polycrystalline films had perpendicular magnetic anisotropy, high coercivity (2 - 5 kOe) and good hysteresis loop squareness. It was established that perpendicular anisotropy constant and coercivity of films depends on substrate thermal expansion coefficient. The wavelength dependence of Faraday rotation (Theta) _F is typical that for cobalt ferrite films and have two maximum: (Theta) _F equals 2,7 deg/micrometers within (lambda) equals 0,5 - 0,53 micrometers and (Theta) _F equals 2,5 deg/micrometers at (lambda) equals 0,8 micrometers , last presents the practical interest and is sufficiently high value. Magneto-optical figure of merit reaches 0,5 deg. at (lambda) equals 0,63 micrometers and 3,0 deg at (lambda) equals 0.8 micrometers . According to achieved results the polycrystalline cobalt ferrite Co_0.7Fe_2.3O₄ films are a good candidate for a magneto-optical storage media.

Strong changes were observed in the Faraday rotation (FR) spectra of multilayered Co/SiO₂ films in comparison with homogeneous Co films: whereas the FR in homogeneous Co films decreased monotonically as the light wave length (lambda) decreased, FR in multilayered films increased with the (lambda) decreasing. The rate of the FR increase with respect to the change in (lambda) was progressively greater the thicker the SiO₂ layers and greater the number of layers.

Polymer films filled with metal nanoparticles were produced both by vacuum co-deposition and plasma enhanced chemical vapor deposition. Films composition and structure were studied by AES, TEM, SEM, Raman scattering and ellipsometry. Information was recorded by both Nd:YAG laser at 532 nm and semiconductor laser at 830 nm. Te, Sb, Sn, Pd, Au-contained films of different composition were produced. Hydrocarbon and fluorocarbon polymers were used. It is shown, that the recording energy is determined by physical properties of metal, its concentration and phase morphology. The polymer matrix properties strongly influence threshold characteristic of media. There are three possible recording mechanisms on the metal-polymer media: ablation, swelling, bubbling. They depend on melting and evaporation temperatures of the metal and decomposition temperature of the polymer. The swelling type media shows the best resolution and high stability, if noble metal is used. For this type media polymer must have a slope of function of viscosity and quantity of decomposition products vs temperature as sharp as possible, while for ablation type media these properties should align with melting and evaporation temperatures of metal.

New photothermoplastic material was made by solved together of three problems: to provide registering material with record high-sensitivity and high-resolution, to provide for inner rastering, to develop the transformation of the phase image to the amplitude one.

Optical properties of molecular J-aggregates of cyanine dyes are investigated intensively at present time. The most characteristic peculiarity of J-aggregates is presence of narrow peak (J-peak) red shifted from the peak of single molecule in absorption spectrum. J-peak is due to exciton absorption (Frenkel's exciton) and its width is defined by effect of motional narrowing) The interest to J-aggregates of pseudoisocyanine (PlC) has been aroused recently by discovery of their huge cubic susceptibility with l)iCOSecOnd decay time.24 The developing of preparation methods for J-aggregates PIG in thin films is actual for practical application. J-aggregates PlC in films of Langmuir-Blodgett or in a polymer matrix have been described recently.58 Temperature and radiation stability of such films allows to carry out investigations of structure, exciton dynamics and their nonlinear-optical properties. One of the methods for study of nonlinear properties of thin films is z-scan technique when real and imaginary parts of third order susceptibility are measured independently . Nonlinear optical properties of two types of i-aggregates prepared in thin films and studied by z-scan technique are described in this paper.

Optimization of photosensitive composition, investigation of film formation conditions and improvement negative polyimide photoresist properties is accomplished. Polyimide photoresist is suggested for producing an interlayer dielectric coating in high density interconnected modules and passivation layers due to a good electrical insulation properties, planarization, high thermal and chemical stability.

Photochromic 6,11-diphenoxy-1-aza-5,12-naphthacenequinone, 6-11-diphenoxy-2-aza-5,12-naphthacenequinone, and 11- phenoxy-10-aza-5,12-naphthacenequinone have been synthesized. The efficiency of photocoloring and photo- decolorizing of these compounds has been determined in comparison with the known 6-phenoxy- and 6,11-diphenoxy- 5,12-naphthacenequinones in toluene, propanol and acetic acid.

Two regimes of vacuum deposition of 1',3',3'- trimethylspiro[indoline-2',3-2H-1-phenanthro-[9,10- b][1,4]-oxazine] (SPO) leading to the formation of amorphous films showing photochromic properties were determined. It was established that at room temperature a thermal decoloration of these films does not occur. It was suggested that the complex absorption spectrum of colored film and the character of its change at a film storage on natural light are due to the formation of different SPO photoinduced form stereoisomers. The long-duration storage of the amorphous film leads to its crystallization with following loss of photochromic properties.

The peculiarities of thin film structure (In₂O₃ + SnO₂)- BSN -(In₂O₃ + SnO₂) are considered in terms of it's application as a reversive storage medium with electrooptic principles of information reading that is the condition of medium element being determined by polarization direction in the ferroelectric.

Photoisomerization kinetics of naphtacenepyridones (NP) embedded into polymer films have been investigated. It is found that the kinetics of photocoloration reactions under single-photon excitation both in cw and femtosecond pulse regimes are similar while they are significantly different from kinetics under two-photon excitation. In the last case it proves to transform only about 12% of the photochromic molecules into colored form. This distinction in photocoloration kinetics seems to be attributable to the differences in photoabsorption cross sections of isomers under single- and two-photon excitation. According to the two-level model of excitation the value of two-photon cross section of NP molecules in form A is estimated to be approximately 0.1 (DOT) 10^-50 sm⁴s at wavelength of 860 nm. The value of quantum yields of photoisomerization and photodestruction was demonstrated experimentally not to be conserved during both writing and erasing photoreactions. It is suggested that the decrease of quantum yields during erasing is due to the kinetic nonequivalence of naphtacenepyridones molecules embedded into polymer host. For this reason a number of readout cycles increases while the erasing process becomes more hard. Two-photon bit-by-bit writing and page-by-page fluorescent reading of information have been realized in multilayered polymer matrices consisting of 1.5 - 2 micrometers photochromic layers separated by 30 micrometers inert polymer layers.

Langmuir-Blodgett (LB) films of naphthacenequinone molecules on highly oriented pyrolytic graphite (HOPG) have been investigated by scanning tunneling microscopy/spectroscopy. It is shown that naphthacenequinone molecules incorporated in LB films are capable to form stable ordered structures on the surface of HOPG substrate. The distinct peak in local density of electronic states has been detected.

The influence of three effects on the behavior of photoisomerization quantum yields of organic photochromic molecules embedded into polymer matrices have been investigated by computer simulation and compared with the experimentally observed quantum yields. First, the reverse photoreaction, second, the non-uniformity of the intensity along the direction of light propagation in the sample volume due to high optical density of the medium and third, the kinetic nonequivalence of photochromic molecules. All three effects cause the decreasing of the quantum yield during reaction. The main effect causing the diminishment of quantum yield during photobleaching of 6- phenoxynaphthacenequinone is the kinetic nonequivalence of photochromic molecules in the polymer host. It is shown that the drop of quantum yield observed in this case leads to significant difficulty of erasing the information while the possible number of readout cycles is increased. The fall of quantum yield of naphthacenequinone embedded into polymer film during photocoloration is caused mainly by the reverse reaction and kinetic nonequivalence of molecules.

In the presentation we describe the microspectrophotometer for studies of efficient yield of two-photon photoreactions of photochromic media, perspective for development of 3D memory devices. The theoretical model allowing estimation of two-photon absorption cross-section of photochromic compounds from induced absorption data in films is considered.

The photochemical behavior of dichromated gelatin and of different aminoacids-chromium (VI) systems was investigated. The photoredox process that takes place between chromium (VI) (complexed or not) and the organic moiety leads to the formation of chromium (V) which is then reduced to chromium (III) likely complexed to the medium. In chromium (VI)- aminoacids systems, the quantum yield (Phi) , that measures the efficiency of a photon at a given wavelength, strongly depends on the reductive properties of the aminoacid. (Phi) is proportional to aminoacid concentration. In irradiated DCG films, the formation of chromium (V) is observed and this intermediate species appears to be surprisingly stable in the polymeric matrix.

The mechanisms of holographic recording in (mainly chalcogenide) amorphous semiconductor films are reviewed including photoinduced structural changes, relaxational structural changes, recharging of localized states in the band gap, and photoinduced anisotropy. The holographic properties in these cases are compared. Different effects of hologram self-enhancement are also considered.

The sharp increase of photoconductivity current fluctuations is observed experimentally in lead molybdate crystals for definite values of exciting radiation intensity. The mechanism explaining the arising of anomalously great fluctuations of photoconductivity current in lead molybdate crystals taking into account the spatial-temporal dependence of photoconductivity current is proposed on the base of quadratic low of photoelectronics recombination. The experimentally observed anomalously great fluctuations of photoconductivity current are explained by 1D soliton arising in the photoconductor.

Under high concentrations of photochromic disubstituted indigo in glassy poly(methylmethacrylate) (0.1 - 0.5 mol.%) photoinduced form thermoisomerization rate and corresponding relaxation rate of optical absorption decrease significantly due to molecular aggregates formation. Three-fold and more acceleration of the thermoisomerization process was revealed under increased photoirradiation doses and related to photoinduced disaggregation of photochromic molecules. The effect may be used for optical image processing, for example, contrast reversal.

The model of condensed photochrom medium with anisotropic optical response arising due to radiationless energy transfer is described. The effect is caused by prevailing of the concentration of photochrom molecules having dipole transition moments parallel to electric vector of the exciting light owing to different migration mobility of electronic excitations of the ground and photoinduced molecule forms.

The influence of film chemical structure and surface modification with P+ ions on optical and masking properties of vacuum-deposited dye films based on benzo[a]phenoxazine derivatives were investigated. Relationship of implantation conditions, surface chemical structure, modified layer thickness and film optical properties was studied. The drastic change of film optical and masking properties in the result of ion implantation is caused by the formation of surface modified layer.

The processes of the electron excitation energy transfer between the cation due molecules in aqueous solutions of polyelectrolytes, surfactants were studied. The dependencies of the efficiency of the energy transfer between the dye molecules were received experimentally. We found that the distribution of the interacting molecules in the investigated systems have the fractal character. The fractal dimension of the investigated systems depends on the concentration of surfactants and polyelectrolytes.

It is shown that the addition of donors (D) into resists composition based on novolac resin and diazonaphthoquinone sulfonate (DQS) ensures the linear increase quantum yield of the DQS decomposition and the light-sensitivity of resist when the ionization potential of a donor decreases. These facts are explained by the exciplex D(DQS)^* formation and its subsequent dissociation on unstable D⁺ and (DQS)^- radical ions transforming into indene carboxylic acid.

The holographic record of gratings on excited triplet (T) annihilating centers in rigid mediums is proposed. The annihilation stage of the reaction T + T yields 0 is visualized by measuring of the diffraction picture dynamics. It has been found theoretically that the second range diffraction maximum is appear in consequence of the nonsinusoidal grating form. The analytical expressions for the intensity of first and second range diffraction maximum are obtained. The fluctuations of the transient grating transmission, (tau) _A, in a porous medium are investigated. The drastic decrease in the disperse (delta) (tau) _A is observed for the system with annihilating excited triplet centers. Two species of the reaction mechanism are studied: static and diffusion--accelerated annihilation. In the second case the reduction of (delta) (tau) _A was greater. The squeezed fluctuations effect induced by additional laser pulse is discussed.

The hologram recording mechanism in the dichromated gelatin layers are discussed. A new technologies are described for red rainbow hologram recording in the photographic emulsion and selfdeveloped dichromated gelatin--glycerol layers. A new method is suggested and experimentally approbated for relief plastic replica of the rainbow hologram fabrication based on the tanning developed or bleached photographic emulsion. This method is modification of the old photographic `bromoil' process. Some aspects of the noncoherent hologram coping on the dichromated gelatin films are discussed too.

Recent results of structural and analytical characterization of AgX (X equals Br, I) microcrystals of photographic emulsions by a number of cryo-analytical electron microscopy (AEM) and image analysis techniques are presented. Monte Carlo simulations of electron beam-AgX interactions have been made for a better understanding of relationships between various signals which can be analyzed in the corresponding AEM modes. Combined cryo-ESI/EDX multielement mapping was performed on AgX grain thin sections and on tabular AgX microcrystals. The contrast imaging under filtering with selected energy windows has been applied to image the morphology, crystal and defect structures of composite tabular AgX microcrystals. Extra reflections at commensurate positions in between the main Bragg reflections and weak diffuse intensity honeycomb contours caused by twins and/or {111} stacking faults in the shell region parallel to {112} grain edges and polyhedral clusters of Ag⁺ interstitials, respectively, were found in selected-area electron spectroscopic diffraction patterns. Low-loss collective excitations due to plasmons and excitons possibly superimposed with interband transitions and many- electron effects were revealed by cryo-EFTEM/EELS. The real and imaginary parts of dielectric permittivity were determined by means of a Kramers-Kronig analysis. Elemental inner shell edges of Ag and halides above 50 eV energy loss have been detected by EELS in accordance with cryo-STEM/EDX- analyses. The local crystal thickness was determined by a modified EELS log-ratio technique in agreement with measurements on grain replicas.

Possible applications of the 3-methyl-3-tert-butylperoxy-1- butynyl silver (PBS) thin films for photovisualization was studied. The images formed on thin films under irradiation were developed by two ways: thermally or using standard methol-hydrochinone developer. The mechanism of slow image inversion during the keeping of PBS thin films is discussed.

AgBr-emulsions with tabular hexagonal microcrystals were synthesized according to the procedure including nucleation, twinning and double-jet crystallization. Parameters which defined the results were established from crystallization theories, mathematical modes of mass crystallization and experimental results. The effects of some parameters were studied.

In the work we have considered the surface photostimulated processes in single- and polycrystals AgHal, CdS, ZnS as well as in the films of Cd_sZn_1-xS resulting in a formation of information storage centers--metallic clusters (Me)_n with n equals 2,3,... < 10. Mathematical simulation of the surface migration of the adsorbed metal atoms has been performed. Prospective media for the storage of optical information are suggested.

Our work demonstrates the influence of presence of stabilizer in the high resolution photographic emulsions and the way of photographic materials processing on the diffraction efficiency of hologram.

Photographic systems with a separate photographic change carriers capture in depth and on a surface of emulsion microcrystals (`core-shell') have a great importance for photographic technology (direct positive, infra-red films and etc.) and also for scientific investigation. We have precipitated AgBr(I) core microcrystals (with AgI content from 0 up to 6 mol.%), which then were subjected to chemical sensitization of various types (reduction, S, S+Au, Au). A sensitometric study of the covered by shell of various thickness and halide composition initial microcrystals has been carried out. An effect of the loss of internal sensitivity is found. A nature of this effect is proposed and ways of its elimination are offered.

The ronnatlon o Frerilcel derects in a bulk or the AgBr inicrocrystal (MC) and on its surrace with participation o the surrace derects Agj1 Br1"2 called silver and brorn kink sites that had partial etrective charge was considered. By minimizing the change or the rree energy or the MC in a conditions o a thermal equilibrium and using the electric neutrality equation.

The conditions of nonequilibrium growth of the new forms of silver chloride microcrystals--stereostructures are determined. At exposure by the mercury lamp characteristic allocation of large particles of photolytic silver on local sites of a stereostructures surface has been found out.

For microcrystals (beta) -AgI are observed three peaks of thermostimulated luminescence (TSL) with temperatures of maximas 100 K, 130 K, 150 K. The analysis of spectral and kinetic characteristics allow assume the different mechanisms of TSL with T < 110 K and peaks 130 K and 150 K.

Presented work is dedicated to the AgCl sensitization rate checking procedure by the reference cyanine dye absorption on the sensitized AgCl grains. The procedure under consideration allows to check a rate of the AgCl chemical sensitization down to the grain size of 0.15 micrometer.

The experimental results about photostimulated regression have been obtained for sulfur-silver centers adsorbed on surface of silver chloride microcrystals. In addition, after this decay monomolecular sulfur-silver centers and low- atomic clusters of silver were formed on the surface of AgCl microcrystals.

Under irradiation the formation of primary intrinsic defects in silver halide solid solutions AgBr_1-xCl_x take place via strong exciton-phonon interaction. Efficiency of these defects formation depend on solid solution composition and within 0 <EQ x <EQ 0.15 dependence on temperature was observed too. Estimation shows efficiency of defects creation is approximately 0.01 for AgCl and noticeably higher for AgBr.

The method of dielectric losses offered van Biezen in an extremity 60-th [ 1], is widely used for a research of the ionic conductivity of the photoemulsion silver halide microcrystals (MC). According to the method, photoemulsion represents the heterogeneous system consisting of conducting silver halide grains, concluded to the insulating gelatine. With overlay of an external electrical field in a such system there is a dielectric dispersion. Complex dielectric permittivity s + i ", where c ' - usual dielectric permittivity, " tgö- the factor of dielectric losses. Frequent dependence of the dielectric losses factors defined by expression [2J: 8" (co) = (g - S) (1 + (cot) asin inx/2) I (1 + 2 (cot) cositoc/2 + (r) 2a) has a maxima under condition of cot 1 , where (s - )- residual between values of static and optical dielectric permittivity 0) - cyclic frequency of an external electrical field; the parameter 0 < oc < 1 , determines a scatter on times of relaxation; 't time of relaxation. The frequency of a maxima of dielectric losses (Fmax) is directly proportional of ionic conductivity ( r) silver halide MC: =Fmax(-E ) 2/q(8c-Eo) Where 81 - dielectric permittivity of gelatine, q- a volumetric long of silver halide. The researches which have been carried out per the last years, have shown, that the ionic conductivity of silver halide MC depends on a number of the factors, such as habit and size of microcrystals, pAg of a solution of synthesis, addition of photogfraphic active substances. From here explicitly follows, that the change of a state of the microcrystal's surface, owing to various conditions of synthesis and adsorption of active substances influences the photographic characteristics emulsion, and also changes of the interstitial silver ions concentration -main carriers of a charge in the silver halide, which, as is known, plays the important role in the generation of the latent image centers.

The process of T-crystals formation includes at least three stages, and the absence though by one of them makes occurrence of T-crystals impossible. These stages are nucleation, transformation of nucleus into a T-crystal and growth of T-crystals.

Photographic properties of AgBr T-crystals and AgBr T- crystals with AgBr(I) lateral shell, doped by Cd(II) ions are investigated. Phenomenological model of the mechanism of an impurity ions influence on properties of a heterocontact in system AgBr/AgBr(I) is offered.

While most people, including this author, hold quite optimistic views of the photochromic industry, very little commercial success has been realized. In Professor Giacomo Ciamician's famous paper on photochemistry of the future, he predicted that photochromic clothing would be popular. It turns out that he was right. His paper was written in 1912 and photochromic clothing was not commercially successful under the early 1990's. These optimistic projections are commonplace. Unfortunately, the commercial successes have not been rapid or frequent. This paper is intended to address some of the critical success factors in achieving photochromic related profitability. The major ingredients of commercial success are an attractive industry and mastery of the specific critical business elements that lead to profitability in that industry.

Light sensitometers with electroluminescent foils as light sources are widely used for controlling film processing in medical x-ray imaging. This type of sensitometers emits trains of light pulses which may cause intermittency effects and reciprocity law failures. The effects were measured for various x-ray films with an especially designed novel light sensitometer. The results show, that there are significant effects for some films, demanding consequences for the construction of light sensitometers equipped with electroluminescent foils.