Proceedings Article | 15 December 2000
Proc. SPIE. 4087, Applications of Photonic Technology 4
KEYWORDS: Diffraction, Visible radiation, Holograms, Holography, Polymethylmethacrylate, Polymers, Ultraviolet radiation, Molecules, Resistance, Absorption
By means of real-time holographic recording, two important classes of photochromic compounds (spiropyrans and
fulgides) have been characterized. For spiropyran molecules, important thickness and writing intensity effects were
observed.
Concerning fulgides molecules, photochemical fatigue resistance in different polymer hosts was investigated. After 10
irradiation cycles, the closed form lost 9, 1 1 , 13 and 35% of its initial absorbance respectively in PS, CA, PMMA and
PVK. For the holographic study, diffraction efficiency in fulgide doped PMMA films was strongly dependent on the
writing intensity: the rise time 'r takes values 25and 7s for respectively 2 and 8 mW/cm2. Optimum fulgide concentration
and writing exposure have been obtained: diffraction efficiency is maximum with a concentration of 2% and an intensity
of 4mW/cm2.
Keywords:Photochromism, photosensitive materials, fulgides, spiropyrans, polymethylmetacrylate, polyvinylcarbazole,
real-time spectrometry, photochemical fatigue resistance, holographic recording.
