POLARIZATION-INDUCED PHOTOCHEMICAL-REACTI ON IN POLYMER SOLIDS - EVALUATION OF A MODEL FOR ROTATIONAL DIFFUSION-CONTROLLED REACTIONS

Intramolecular photodimerization of the photochromic molecule 9-hydrox ymethyl-10-{(naphthyl methoxy)methyl} anthracene (HNMA) exhibits photo selectivity upon irradiation with linearly polarized light in tile gla ssy state of poly(methyl methacrylate) (PMMA). The induction efficienc y, the dichroic absorption and the reaction rates of this intramolecul ar photodimerization were obtained from the two polarized components o f the absorbance of anthracene moieties on HNMA. The reorientational r elaxation rates of the molecule were also measured by using the so-cal led annealing-after-irradiation method. These experimental results wer e compared to the theoretical prediction of a rotational diffusion-con trolled reaction model proposed recently for the polarization-induced photochromic reactions in liquids.