Glasses are defined as amorphous solids, obtained from quenching of liquids. The production of glass is a well known process and starts with the melting of oxides. The glass is formed when these molten substances are quenched, preventing crystallization. Lithium disilicate glass (Li2O.2SiO2) has been extensively investigated due to the large difference between Tg and Tc, besides several technological applications. The investigation of the pressure effect over the structure and properties of glasses is of great interest from both practical and theoretical points of view. This work aims to analyze the effect of high pressure (up to 12 GPa) in structural and physical properties for large volume samples of lithium disilicate glass. The experimental results were obtained using a multianvil high pressure apparatus up to ~12 GPa at room temperature. Previous results of samples processed using toroidal type high pressure apparatus up to 7.7 GPa were used for comparison. Thermal analysis was used to identify the glass transition (Tg) and crystallization temperatures (Tc). The structural changes induced by pressure on the amorphous phase were investigated by X-Ray diffraction, Raman and infrared spectroscopy. The differential thermal analysis results show that increasing the pressure from 7.7 GPa to 12 GPa affects the glass transition and crystallization temperature. Infrared spectroscopy indicates subtle differences induced after densification at higher pressures. X-ray diffraction data using synchrotron radiation allowed the investigation of the effect of high pressure on the total pair distribution function G (r) for the sample processed at 12 GPa.