The Structure of Dried, Monolithic Silica Gels, Studied by Raman Spectroscopy

We have studied the structure of dried, monolithic silica gels using Raman spectroscopy in combination with measurements of density specific surface area and pore size. Depending upon the chemical composition of the gel solution, the gelation procedure and the drying temperature and atmosphere, monolithic silica bodies with densities ranging from 0.03 to 2. 2 g/cm3 can be prepared. The structural characteristics, e.g. network structure, defects, and Si-OH groups, will be compared with those of bulk vitreous silica.