Abstract
Glasses were prepared from the system xLa2O3·(1-x)P2O5, where 0.00≤x≤0.30 (mole fraction), and densities, refractive indices and glass transition temperatures were determined. Inflections in the property/composition trends were observed at x approximately 0.15 La2O3. Raman spectra indicate that the phosphate network evolves from a cross-linked ultraphosphate to chain-like metaphosphate with increasing x. The property and spectral trends are interpreted with respect to the La-coordination environment, which appears to change from isolated La-polyhedra to a La-O-La subnetwork when x≥0.15.