Abstract
Reactions in polymer solid are different from those in solutions because the mobility of polymer molecules is so restricted that reactivities vary in the local environment and site by site. One of the factors influencing on their reactivity is free volume of the polymer, however free volume has not been quantitatively estimated up to now. In this paper, azobenzene in polymethyl methacrylate was used as photochromic probe. Azobenzenein PMMA were isomerized with photoirradiation and the change in the absorption spectra of azobenzene was observed Quantum yield distribution for the photoreaction was obtained by analyzing the observed curve of isomerization, and the effect of annealing temperature on their quantum yield distribution is also described.