VARIATION OF MICROENVIRONMENT AROUND AURAMINE-O MOLECULES DOPED IN SILICA PREPARED FROM TETRAMETHOXYSILANE

Silica gel doped with Auramine O (AuO), which is known as a microscopi c viscosity probe through fluorescence spectra, was prepared by the so l-gel method using tetramethoxysilane (TMOS) as a starting alkoxide. F luorescence spectra from the starting solution to the dry gel were mea sured to pursue the variation of microscopic viscosity around the AuO molecules during the sol-gel process. The fluorescence intensity of Au O did not change at the gelation point, indicating that the microscopi c viscosity around AuO did not change during the sol-to-gel transforma tion. The intensity was, however, increased largely in the drying proc ess; the internal motion of AuO molecules became largely restricted by the surrounded silica matrix during the drying process.