APPLICATIONS OF ORGANIC BRIDGED POLYSILSESQUIOXANE XEROGELS TO NONLINEAR-OPTICAL MATERIALS BY THE SOL-GEL METHOD

Sol-gel precursors of alpha,omega-bis(triethoxysilyl)-bridged polysilsesquioxanes containing a sidechain chromophore with known second-order nonlinear optical properties were synthesized. Thin films were formed from these precursors without the addition of other sol-gel forming components. The films were poled while curing at elevated temperatures. Poled films derived from 4-nitroaniline or 2,4-dinitroaniline chromophores resulted in sol-gel based materials with d(33) coefficients of 35-37 and 9-10 pm/V, respectively. Electrooptic coefficients r(33) (1.3 mu m) extrapolated from d(33) were calculated to be 9-10 and 2-2.5 pm/V, respectively.