The density-driven structural transformations in the magnesium silicate glass MgSiO3 will be investigated at pressures increasing to 17.5 GPa. This glass is one of a family of geophysically important silicate materials that form a significant component of the Earth's mantle. As the density is increased, a disruption of the tetrahedral silicate network is expected to be observed as the Si-O coordination number starts to increase above four. The results will be used to inform molecular dynamics models of MgSiO3, a material that is used as a reference for simulating the high-pressure behaviour of hydrous silica melts under geophysical conditions. If necessary, new interaction models will be developed for deducing the mechanisms of network collapse.