PROBING THE CYBOTACTIC REGION OF PRODAN IN TETRAMETHYL ORTHOSILICATE-DERIVED SOL-GELS

6-Propionyl-2-(dimethylamino)naphthalen (PRODAN) is an extremely solve nt sensitive probe. Changes in its photophysical characteristics are u sed to probe the microenvironment of the sol-gel matrix as a function of aging time. These results clearly demonstrate that PRODAN senses a distribution of microenvironments within the sol-gel matrix. The ensem ble of domains are evident immediately after gelation up until the dry ing stage. The extent of this microheterogeneity varies as a function of aging time. Steady-state emission anisotropy and time-resolved emis sion data provide detailed information on how the various stages of th e sol-gel process affect the photophysics of PRODAN.