Spectroscopic properties of copper ions in ZnO–ZnF2–B2O3 glasses

ZnO–ZnF2–B2O3 glasses containing varying concentrations of CuO ranging from 0.2 to 2.0 mol% were prepared. A number of studies viz. differential scanning calorimetry, optical absorption, ESR, IR and Raman spectra, magnetic susceptibility and also the dielectric breakdown strength at room temperature in air medium have been carried out as a function of copper ion concentration. From these studies, the variations in the values of glass transition and crystallization temperatures, optical band gap and the shifting of symmetrical bending vibrational frequency bands of borate groups were observed with increase in concentration of CuO. The analysis of these results indicated that copper ions mostly exist in Cu2+ state in theses glasses when the concentration of CuO ⩽ 0.8 mol% and above this concentration copper ions seem to subsist in Cu+ state.