AZO POLYMERS FOR REVERSIBLE OPTICAL STORAGE .1. POLY[4'-[[2-(ACRYLOYLOXY)ETHYL]ETHYLAMINO]-4-NITROAZOBENZENE]

Poly[4'-[[2-(acryloyloxy)ethyl]ethylamino]-4-nitroazobenzene] (pDR1A) is used as an example to demonstrate the ability of amorphous high-T(g) azoaromatic-containing polymers to reversibly store optical information. Writing, reading, erasing, and rewriting processes are performed using laser beams on a pDR1A film. This ability is based on the well-known trans-cis-trans isomerization process which was previously studied on liquid-crystalline polymers containing azoaromatic groups. Liquid crystallinity is not a necessary condition for optical storage. As well, erasing can be performed optically, eliminating the need to heat the polymer sample. The writing and erasing are statistical processes, and the level of optical anisotropy induced depends on the photon flux directed at the sample. The time evolution of the writing process is investigated. A computer simulation of these processes is performed taking into account a relaxation process in which some of the reoriented trans molecules are randomized by thermal motion. The computer model replicates the general features of the optical storage processes. Possible applications and future work on this class of polymers are also discussed.