Reflection spectra of various kinds of oxide glasses and fluoride glasses in the vacuum ultraviolet region

Abstract

Reflection spectra of silicate, borate, phosphate, fluorophosphate and fluoride glasses are studied in the spectral region of 2–13 eV in order to understand their dispersion behaviors in the visible region from the point of view of atomic structures. The absorption bands due to bridging oxygen ions or fluorine ions are found at 11.6 eV and 10.4–9.5 eV in silicate glasses, at 10.2 and 8.8 eV in borate glasses, at 9.5 eV in phosphate glasses, at 11.2 eV in fluorophosphate glasses and at 11 eV in fluorozirconate glasses. In silicate glasses, the bands due to nonbridging oxygen ions are found in the region 8.8-4.9 eV. They shift to lower energies with increasing ionic radius, in the order of Ca 2+, Sr 2+ and Ba 2+, for the glasses containing low valency cations, while they shift to higher energies with increasing ionic radius, in the order of Ti 4+, Zr 4+ and Th 4+ or in the order of Nb 5+ and Ta 5+, for the glasses containing high valency cations. In glasses containing large amounts of PbO, strong bands due to PB 2+ ions appear in the lower energy regions of 6.3–5.6 eV and 5.2–4.7 eV.