Silica glass is one of the most widely studies amorphous materials. It is the archetypal glass former, comprising a network of corner-shared SiO4 tetrahedra. Recently a lot of attention has been paid to discontinuous changes in amorphous structure, this is the phenomenon of polyamorphism. The exact nature of these structural changes is still unclear but for SiO2 these trasntions are porosed at pressured well below those where changes in short-range order (coordination number) have been observed. In this proposal we will continue our measurements of pure SiO2 glass at high pressure. We have collected data at 11 and 24 GPa and these data show large changes in structure. We will collect new data at pressures of 8, 15 and 20 Gpa to determine whether these changes are continuous or discontinuous.