Transformation of Boron Oxide B2O3 under High Pressure and High Temperature

This paper describes the transformations of boron oxide B2O3 under high pressure and high temperature. We have found that boron oxide B2O3 with cubic system is transformed into hexagonal and orthorhombic B2O3 under a pressure of 5.0 GPa and a temperature of 800 ℃. Under pressure of 4.0 GPa and temperature of 1000 ℃, cubic B2O3 is transformed into amorphous state, whose colour is white. Moreover, structural changes with increasing temperature and pressure, and method of quenching from a fusing state under high static pressure are discussed.