PHOTOCHEMISTRY AND MULTIPLE HOLOGRAPHICAL RECORDING IN POLYMERS WITH PHOTOCHROMIC PHENOXY-NAPHTHACENE-QUINONE SIDE-GROUPS

The photochromism of phenoxy-naphthacene-quinones in solution was inve stigated and compared with that of polymers in which one of these comp ounds was incorporated as a side group, through flexible (CH2)(n) spac ers of various lengths. The polymers studied were polystyrene (PS), po ly(methyl methacrylate) (PMMA), and polysiloxane (PSX). Up to 90% phot ochrome side groups could be incorporated in some of these polymers. T he polymers were studied both in solution and as flexible films. The q uantum yields in solutions of one of phenoxy-quinones was about 0.6 fo r trans-->ana, and about 0.10 for ana-->trans. The photoconversion tra ns-->ana is only slightly slowed down in solutions of the polymers, bu t much more so in films. The rates of photoconversion observed in film s, relative to a solution of the photochrome proper were as follows: P S, 12; PMMA, 25; PSX, 50; solution, 100. These rates vary slightly wit h the concentration of the photochrome but increase with increasing sp acer length in PMMA and decrease in PSX. The glass transition temperat ure may play an important role. Multiple holographic recording on the polymers was investigated.