ABSORPTION AND FLUORESCENCE-SPECTRA OF RHODAMINE-B MOLECULES ENCAPSULATED IN SILICA-GEL NETWORKS AND THEIR THERMAL-STABILITY

The absorption, fluorescence and fluorescence excitation spectra of rhodamine B molecules encapsulated into -O -Si -O - networks (by the sol-gel processing of a tetraethyl orthosilicate (TEOS) solution containing rhodamine B) were measured and their thermal stability was investigated. The absorption and fluorescence spectra of rhodamine B measured during the sol-gel process are similar to those of rhodamine B adsorbed on porous Vycor glass and dissolved in ethanol solution. These results indicate that the rhodamine B molecules are encapsulated in a stable for in the - O - Si - O - networks of the silica gel during the gelation of the TEOS solution. The thermal stability of the encapsulated rhodamine B molecules is enhanced. © 1990.