The structural influence of chromium ions in lead gallium phosphate glasses by means of spectroscopic studies

PbO–Ga2O3–P2O5 glasses containing different concentrations of Cr2O3 ranging from 0 to 1.0 mol% were prepared. A number of studies viz., differential thermal analysis, infrared, optical absorption, ESR and Raman spectra of these glasses have been carried out as a function of chromium ion concentration. The analysis of the results of these studies indicated that chromium ions mostly exist in Cr3+ state in these glasses when the concentration of Cr2O3 ⩽ 0.4 mol% occupy octahedral positions and above this concentration chromium ions seem to subsist in Cr6+ state and occupy tetrahedral positions with CrO42- structural units.