Organosilicon Polymeric Nonlinear Optical Materials for Optical Switching andModulation

摘要

The objective of the project was to develop new polymeric materials for second-order nonlinear optical (NLO) applications, specifically electro-optic applications. Alkoxysiloxane derivatives of organic azo dye chromophores were synthesized and used to prepare NLO siloxanes by the sol-gel reaction with a siloxane polymer. The dipole moments and polarizabilities and hyperpolarizabilities of the chromophores were calculated by semi-empirical quantum mechanical modeling. A novel approach using interpenetrating polymer networks (IPN) combining a sol-gel based NLO siloxane with a thermally crosslinkable NLO azo dye attached epoxy network, as stable second-order NLO materials was also introduced. In two of these systems, the addition of another crosslinkable azo dye component to boost the NLO density was investigated. The materials were processed into thin films on substrates and simultaneously oriented by corona poling and thermally cured at temperatures up to 220 deg C. The NLO siloxanes showed relatively weak optical nonlinearities while the electro-optic coefficients of the IPN systems were reasonable large and temporal stability was excellent-the materials showing considerable promise for practical applications.