POROUS GEL SILICA, A MATRIX FOR OPTICALLY-ACTIVE COMPONENTS

The sol-gel process has been used to prepare optically active components in a silica matrix. In most cases this involves introducing an optically active material such as an organic dye into the initial sol prior to gelation. An alternative sol-gel route involves first the preparation of porous, pure silica monoliths which can then be impregnated with the desired organic or inorganic material. Critical to the usefulness of this material is a knowledge of the properties, such as thermal stability, UV/vis/nIR spectra and pore size. The structural evolution of these porous silica monoliths prepared by the sol-gel process is presented as a function of process temperature. Sample preparation and thermal treatments are briefly described, and results of sample characterizations are given in detail. Results of this study and their implications for the usefulness of the materials are discussed. © 1990.