ELECTRON-PARAMAGNETIC RESONANCE AND MICROHARDNESS OF BINARY VANADIUM TELLURITE GLASSES

Electron paramagnetic resonance (EPR) spectra and microhardness measurements of binary vanadium tellurite (V2O5-TeO2) glasses have been taken. The spectra are typical of V4+ ions present in vanadyl (VO2+) form in the glass. Sufficiently resolved spectra are obtained only for glasses with low concentrations of V2O5 (less-than-or-equal-to 30 Mol% V2O5). Hyperfine lines begin to overlap with the increase in V2O5 and finally collapse for higher concentrations of V2O5. EPR parameters have therefore been evaluated only for low concentrations of V2O5. MiCrohardness of V2O5-TeO2 glasses decrease with increasing V2O5 content. The microhardness of 60V2O5-40TeO2 glass is less than that of 60MoO3-40P2O5 glass reported by Selvaraj and Rao. Both microhardness and EPR studies indicate that the covalency of V-O bonds decreases with increasing V2O5 content.