Gel silica glasses of type VI have been widely used in making laser or NLO dye doped devices by the post-doping method. Both mechanical and optical properties of the as-prepared optical materials can be improved by introducing a third phase into the essentially porous matrix through impregnation. In our study, we have used three different phases to fulfill this purpose: i.e., polymer, sol and ormosil. The finished materials are characterized in relation to their textural structures, bulk structures, phase interaction and susceptibility to environmental impurities such as water. Our results have shown that pores of the initially porous matrix are partially or fully eliminated depending on the type of phase impregnated. In both sol and ormosil impregnated samples, the primary substrate phase interacts with the secondary impregnated phase through the formation of Si-O-Si bonds via dehydroxylation of silanol groups from the two phases. The organic component from the ormosil may also interact with the primary inorganic-based substrate via molecular forces such as hydrogen-bonding. In the PMMA-impregnated materials, surface silanol groups from the gel matrix interact with ester carbonyls of PMMA through hydrogen-bonding. Bulk structures of the primary and impregnated phases are well retained. PMMA-modified samples are hydrophobic; ormosil modified samples are hydrophobic to some extent depending on the actual organic groups; but sol-modified samples are hydrophilic due to the exposed surface silanol groups. In general, organically modified optical composites are best used in the near UV and visible region and their application in the near IR is restricted to some extent due to the overtone and combination vibrational energy absorptions by both the organic and inorganic species present in the materials.