SUPPORTED SOL-GEL THIN-FILM GLASSES EMBODYING LASER-DYES .1. A NEW FAST METHOD FOR THE PREPARATION OF OPTICALLY CLEAR POLYSILOXANE THIN-FILM GLASSES

Alkoxysilane monomers and water were reacted directly, at 60-80-degrees-C, using stoichiometric and sub-stoichiometric ratios of water to siloxane. Following partial polymerization and distilling-out of the corresponding alcohol, the viscous polymer formed within a few minutes and could be spin-cast onto a support. Completion of the polymerization and cross-linking processes was accomplished within a few hours at 60-70-degrees-C. Upon introduction of a laser dye into the reaction mixture, a chromophore-embodying glass was attained. No additive or surfactant was required to eliminate the typical fracturing of the glasses during the curing step. The process was carried out with single layer of typical thickness of 10-25-mu-m, as well as with multilayered assemblies of varying indexes of refraction and total thickness up to 50-mu-m. The absorbance and fluorescence spectra of these laser-dye-loaded glasses were typical of monomeric chromophores, only slightly shifted, even at high concentrations of the dyes (> 10(-2) M). The convenient features of this synthetic method are its quickness and simplicity, its capability to maintain high concentrations of discrete guest molecules (> 10(-2) M) in the glass, and the additive-free nature of the dye-embodying glass films (up to 25-mu-m) prepared by it. This method provides a promising route for nonlinear optics applications such as a two-dimensional dye laser system.