EXCITED-STATE DYNAMICS IN THE STRUCTURAL CHARACTERIZATION OF SOLID ALKYLTRIMETHOXYSILANE-DERIVED SOL-GEL FILMS AND GLASSES CONTAINING BOUNDOR UNBOUND CHROMOPHORES

A series of alkyltrimethoxysilane-derived sol-gel glasses and films co ntaining included (pyrene) and covalently bound ((1-pyrenylmethyl)trim ethoxysilane, 1) fluorescent dopants have been prepared. The structure s of these doped sol-gel films are affected by (1) the manner of dopan t incorporation into and dispersion throughout the matrix, (2) the loc al polarity of the dopant, and (3) the curing method. The dopants (pyr ene and 1) are well-dispersed throughout the glasses: excimer emission is not observed in the final films. The polarity of the dopant is pri marily influenced by the silicon-oxide matrix rather than the identity of the alkyl group in the silane precursor. In the pyrene-doped films , a modest decrease in polarity is observed as the silane alkyl chain length is increased. Corona poling at elevated temperatures during cur ing results in the highest values of emission anisotropy; dopant molec ules in films corona-cured at 60-degrees-C undergo the least amount of rotational diffusion during their excited-state lifetimes.