A 3-(trimethoxy-silyl)propyl methacrylate (TMSM)-methylmethacrylate (MMA)-tetramethyl-orthosilicate (TMOS) hybrid glass, has been prepared using a sol-gel process. In order to study the influence of each of the inorganic matrices, the gels obtained from TMOS and TMSM have been studied separately, the hybrid compound, they have been investigated using Raman spectroscopic, FT-IR and NMR techniques. The networks formed in both TMOS and TMSM gels have been identified. Upon condensation of TMOS a tridimensional array including defect was formed, that results in a certain discontinuity of the material. Nevertheless, the characteristics of this structure have that of molten quartz (glassy silica). By contrast, room temperature condensation of TMSM gave rise to several structurally different species in suspension in the gel. The species have been identified. The insertion of TMSM in an organic network modified its degree of periodicity. The integration of TMOS into a silica network occurred through the formation of rings which link together various silica blocks originated from TMOS. Interpretation of Raman diffusion data shows that the glass still contains non-condensed silanol groups and that low molecular weight cyclic, caged polysilsesquioxanes are formed from condensed TMSM. No organic-inorganic phase separation has been observed. The organic part of the glass has been investigated by Raman Spectroscopy from a microscopic point of view. It has helped understand the competition between condensation and polymerization, and it has been shown that polymerization was not fully completed. This has been confirmed by DSC. Raman spectra have also shown that the inorganic network was mainly three-dimensional. NMR studies confirmed that condensation occurred several times on the active Si O bonds.