Optical Energy Transfer and Photochromism in Doped Sol-Gel Glasses

ABSTRACTOrganically doped sol-gel glasses are investigated by optical absorption and time-resolved fluorescence depolarization measurements. Silicate and aluminosilicate glasses have been doped with quinizarin (Q) and aluminum phthalocyanine chloride (CAP). The structure and bonding in these inorganic sol-gel solids is different from that in frozen liquids and organic polymers, and the unique dynamics of these systems are a motivation for this study. Both rotational dynamics and optical energy transfer of doped chromophores in sol-gel glasses are investigated by time-resolved fluorescence depolarization measurements. Since the dipole-dipole energy transfer rate is very sensitive to transfer distance, these measurements are used to probe the spatial distribution of dopant molecules within these solids. We also present photochromic results on aluminum phthalocyanine chloride doped silicate sol-gel glasses and discuss possible uses as an optical power limiting material.