R3: High-pressure science and deep Earth’s material

[R3P-09] Refractive index measurement of SiO₂ glass at high pressure

*Takeshi Sakai¹, Hideto Mimori¹ (1. Ehime Univ., GRC)

Keywords:Refractive index, Diamond anvil cell, SiO2 glass, coordination number

Refractive index of SiO₂ glass was successfully measured up to 70 GPa using optical interferometric signals in the diamond anvil cell. The refractive index of SiO₂ glass increases linearly with density up to 20 GPa. At pressures above 20 GPa, however, it begins to deviate from the linear relationship and becomes consistent with that of Stishovite. This trend corresponds to the change in the coordination number of Si in SiO₂ glass from 4 to 6. It shows that refractive index measurements under high pressure can provide insight into the structural changes of SiO₂ glass under high pressure.