HIGH-PRESSURE LOADING OF ORGANIC-DYES INTO A SILICA MATRIX

High density, transparent and crack-free compacts of silica gel doped with naphthazarin, quinizarin and rhodamine 6G, were produced by sol-g el synthesis with high pressure at room temperature. Compacts are very stable, being resistent to polishing and leaching by ethanol and acet one. They show optical properties, as absorption and fluorescence, sim ilar to those at dilute solutions, indicating that the dyes are disper sed in the silica matrix as individual molecules. Heat treatment to 15 0 degrees C for 1 h led to almost no degradation. (C) 1997 Elsevier Sc ience B.V.