CROSS-LINKABLE, NONLINEAR-OPTICAL COPOLYMERS - PROCESSING, CORONA POLING, AND 2ND-HARMONIC GENERATION STUDIES

Polymethacrylate copolymers, containing nonlinear optically active 4'- dialkylamino-4-nitroazobenzene side groups and crosslinkable 2-butenyl side groups were synthesized and characterized. Films of these copoly mers can be thermally crosslinked at elevated temperatures and photoch emically crosslinked by exposure with UV light. Both methods allow the control of the crosslinking density. A precrosslinking step, prior to the corona-poling step, can be applied to optimize alignment and rela xation of the chromophores. During corona-poling, the temperature depe ndence of the second harmonic generation (SHG) of an Nd-YAG laser (1.0 64 mum) was studied for films with different degrees of precrosslinkin g. Depending on the conditions of precrosslinking, the SHG signal inte nsity and the alignment stability can be maximized. (C) 1993 John Wile y & Sons, Inc.