The semi-intercalation of an azo-dye Disperse Red 1 (DR1) molecule into a biopolymeric material made of
deoxyribonucleic acid (DNA) complexed with the cationic surfactant hexadecyltrimethyl-ammonium chloride
(CTMA) formulated recently1-3 has successfully explained the main experimental results4 of laser dynamic
inscription of diffraction gratings: short response time, low diffraction efficiency, single-exponential kinetics
and flat wavelength dependence.5 In this paper we generalize the analytic model of Ref.2 to account for a
more realistic dynamics of DNA-CTMA matrix. To this end we extend the model of paper5 by including into
it probabilistic features of local free volume in DNA matrix which characterize, in a simple way, the spatial
distribution of local voids which, in turn play the central role for the kinetics of photoinduced trans-cis-trans
cycles of DR1 dye under the polarized laser light illumination. We discuss a stochastic master equation which
generalizes the simple model of Ref.2 and address briefly the topic of non-exponential grating inscription in
modelling and in recent experiments.
The semi-macroscopic mechanisms responsible for the surface relief gratings (SRG) formation on azobenzene-containing
films are far from deep understanding.1 We present the results of experimental studies of SRG in
PMMA and PVK polymeric matrices. The Monte Carlo (MC) kinetics of polymeric movements is reported for
recently proposed model,2 which mimics the effect of mass transport along the direction of light modulation,
resulting from multiple trans ↔ cis photoisomerisation cycles of functionalized dyes. We show that the model,
symmetric on "microscopic" level, leads to a directed mass transfer from bright to dark places. Preliminary
studies show that the centers of mass of polymer chains undergo a normal diffusion under the light illumination.
No global light-induced ordering of polymeric chains was detected. MC studies were performed for a system
consisting of half a million of model monomers.