PERMANENTLY POLED FULLY FUNCTIONALIZED PHOTOREFRACTIVE POLYESTERS

Crystallization and phase separation are severe degradation mechanisms of photorefractive (PR) guest-host systems. Additionally, the respons e time of PR guest-host systems is in some cases limited by a large co ntribution of slow chromophore reorientation to the PR effect. The syn thesis of fully functionalized systems with glass transition temperatu res well above room temperature is a way to restrict these degradation mechanisms and to reduce the PR effect to a pure charge generation an d transport phenomenon. We present novel, fully functionalized PR poly mers based on polyester. Permanent poling of the systems is demonstrat ed and quantitatively investigated. The PR properties are measured by degenerate four-wave mixing and two-beam coupling experiments as a fun ction of the external electric field and the degree of permanent polin g. One of the systems shows response times of approximately 200 ms wit h Delta n = 1 x 10(-3). To our knowledge, this work presents the first characterization of PR efficiencies for fully functionalized polymers as a function of the permanent Pockels coefficient chi((2)) (-omega;o mega, 0). (C) 1998 Optical Society of America [S0710-3224(98)01310-1].