Silica gels have been obtained in our laboratory by the hydrolysis and polycondensation reaction of a silicon organometallic compound in an alcoholic medium. Solvent is then released from gel under hypercritical evacuation in an autoclave. Firing time is adjusted to obtain samples whose density varies between 0.3 and 2.2. So that, materials with various textural properties (specific surface area, porosity, average pore radius) are available. Experimental conditions which allow gels free of cracks to be obtained after filling by various solvents have been studied as a function of solvent interfacial energy and gel density. Diffusion of aqueous solution in cylindrical samples is then studied. The water-gas boundary in the sample is followed using a video-camera coupled with a computer. Finally, the elaboration of doped silica glasses from filled samples is described.