The evolution of the Raman spectrum of 3-(trimethoxysilyl)propyl methacrylate (TMSPM) during polymerization processes which take place in different chemical reactions is reported. TMSPM is a monomer which has both a methoxide function and a carbon-carbon double bond and is of great interest as precursor to obtain organic-inorganic hybrid glasses hosting chromophores or optically active molecules for a large variety of photonic applications. By changing the reaction conditions, the hydrolysis of TMSPM is achieved by means of polar solvents, or an organic polymerization by using a radical starter: according to the process, the optical, mechanical and chemical properties of the final product show large variations which can be tailored for specific uses. These reactions were monitored through micro-Raman spectroscopy and a correlation between the vibrational spectra and the degree of organic and inorganic polymerization was obtained.