An X-ray diffraction study of bismuthate glasses

Bismuthate glasses in various systems are considered. The influence of the glass composition variation on the short-range order in bismuthate glasses was studied using XRD. A comparison of the total pair correlation functions for glass compositions in the Bi2O3-SrO-CaO-CuO, Bi2O3-PbO, Bi2O3-CuO, Bi2O-TiO2, and TiO2-Bi2O3-PbO-CuO systems indicates that the average first neighbour Bi-O distance shifts from 0.22 to 0.24 nm with increasing Bi2O3 content. For glasses with high concentrations of Bi2O3, mainly BiO6 polyhedra are formed. For low Bi2O3 concentrations, a transformation in the arrangement of the network occurs due to the strong influence of the modifier oxides, and the shorter bridging bonds dominate. This explains their better glass forming ability. 42 refs