Infrared, Raman and XPS spectroscopic studies of Bi2O3-B2O3-Ga2O3 glasses

Glasses with compositions 60Bi(2)O(3)-(40-x)B2O3-xGa(2)O(3) (x = 5, 10, 15, 20 mol%) are prepared by conventional melting method. The thermal properties are investigated by differential thermal analysis (DTA) and the structures of the glasses were probed by Infrared, Raman and X-ray photoelectron spectroscopy (XPS). The results show that density, refractive index and optical basicity increase with the increase of Ga2O3. The glass transition temperature (T-g), the onset crystallization temperature (T-x), Delta T (T-x-T-g) decrease with the content of Ga2O3. The cut-off edges in ultraviolet and infrared shift to longer wavelength with the increase of Ga2O3. On the other hand, the addition of Ga2O3 causes a progressive coordination number change of the boron atom from 3 to 4. XPS result indicates both Bi5+ and Bi3+ exist in 5 mol% Ga2O3 content, while Bi5+ amounts decrease with the increase of Ga2O3 contents. The glass is mainly composed of [BiO6], [BO3], [BO4] and [GaO4] polyhedra. Glasses are supposed to have layer structure. [BO3] triangle and [BO4] tetrahedra may be located between the [GaO4] tetrahedral and [BiO6] octahedra to prevent crystallization and to compensate electric charge. (C) 2009 Elsevier Masson SAS. All rights reserved.