Spectral properties of PbO-P2O5 glasses

The optical absorption spectra of xPbO-(100 − x) P₂O₅ glasses where x = 5, 10, 15, 20, 25, and 30 is reported. The spectral absorption of these glasses was measured in the spectral range 300-900 nm at room temperature. Optical absorption spectra show that the absorption edge has a tail extending towards lower energies. The edge shifts nearly linearly towards higher energies with increasing PbO content. The degree of the edge shift was found to depend on the PbO content and is mostly related to the structural rearrangement and the relative concentrations of the glass basic units. The optical energy gap increases, from 2.55 to 3.05 eV by increasing PbO content from 5 to 30 mol%. The width of the localized states is decreased by increasing PbO content.