Reversible holographic recording in photochromic spiropyran-doped polymers

Summary form only given. Photochromic materials (PM) based in spiropyrans are of great interest in holography and image processing. They are used principally as real-time time reversible holographic media or nonlinear filters due to their saturable adsorber behaviour. Spiropyran compounds are molecules that contain two ring systems sharing a common bridgehead atom. This atom is fully saturated i.e. it can not be conjugation between any double bonds in one ring with double bonds in the second ring. In general, spiropyran dyes absorb in the UV region but not in the visible. Upon UV illumination, the spiropyran undergoes heterolytic cleavage of the carbon-oxygen bond to form the colored isomer (merocyanine). We present a detail study of the linear and nonlinear optical properties of spiropyran dye doped in poliure-tane polymer with several radicals attached to the molecule. Fabrication of spiropyran dyes is difficult, time-consuming and expensive, we use a an ultrasound-induced process that reduces dramatically the fabrication time and cost.