Spectroscopic investigations of barium aluminophosphate glasses containing vanadium, iron and manganese oxides

Abstract

In three ternary systems Ba(PO3)2-Al(PO3)3-T-oxide (T = Transhion element = vanadium, iron, manganese) the Ba/Al phosphate ratio was varied at constant T-oxide content, as well as the T-oxide content at constant Ba/Al phosphate ratio. Optical and ESR spectroscopic investigations as well as thermal expansion and Tg measurements were carried out. The relationship between glass composition and network strength differs principally from that in silicate glasses in some respects and finds corresponding interpretation. At low T-oxide concentrations the interaction between the T-ions and the surrounding oxygen ions decreases with increasing network strength (i.e. with increasing substitution of aluminum for barium). T-complexes are generally present in glasses in strongly distorted symmetry. Thus, for V^4+O6- octahedra distortions exhibit besides tetragonal distortion a significant share of orthorhombic asymmetry. For higher T-oxide concentrations glass properties and structure are characteristically influenced by valence ratios and coordination changes.