Raman spectroscopy of copper phosphate glasses

Abstract

Raman spectra of binary copper phosphate glass samples, xCuO .(1-x)P2O5, having x = 0.4, 0.5, and 0.55 and Various [Cu2+]/[Cu-total] ratios have been measured. The Raman spectra of the samples changed with changing [Cu2+]/[Cu-total] ratio as well as CuO content. The smaller ionic size and the greater charge of the Cu2+ ion than those of the Cu1+ ion create larger in-chain P-O-P bond angles and smaller out-of-chain PO2 angle as well as greater Cu-O field strength. Differing local structures of Cu1+ and Cu2+ ions in phosphate glass results in a variation of Raman spectra of the glasses depending on the [Cu2+]/[Cu-total] ratio. Also, a decrease in phosphate chain length with increasing CuO content affected the Raman spectra of the glasses. Although the crystallization of the samples is not detected in the X-ray diffraction, the overlapping bands in the Raman spectra of the 0.55 CuO samples are attributed to crystalline phases.