A gel of composition 3CaO . 2SiO(2) was synthesised by means of sol-gel route involving hydrolysis of tetramethyl orthosilicate (TMOS) with calcium nitrate in alcoholic medium, and polycondensation reaction. The gel was submitted to DTA and TGA analysis and the resulted material was examined by FTIR spectroscopy and X-ray powder diffractometry. The thermal treatments required for the gel into glass conversion led to a partially devitrified product. The XRD analysis showed that the structure obtained is highly depolymerised.