Properties and structure of copper ultraphosphate glasses

The structures of xCuO · (1 − x)P2O5 glasses (0 ⩽ x ⩽ 0.50) prepared in vacuum sealed silica ampoules were investigated using vibrational spectroscopies. With the addition of CuO, both infrared and Raman spectra indicate a systematic transformation from a three-dimensional ultraphosphate network dominated by Q3 tetrahedra into a chain-like metaphosphate structure dominated by Q2 tetrahedra. IR spectra clearly show two distinct Q3 sites with bands at 1378 and 1306 cm−1, assigned to PO bonds on isolated Q3 tetrahedra and PO bonds on Q Cu 3 tetrahedra that participate in the coordination environments of the Cu-octahedra, respectively. As CuO content increases, the intensity of the PO band associated with the Q Cu 3 tetrahedra increases to a maximum x ∼ 0.33, then decreases with a concomitant increase of the intensity of the band at 1265 cm−1, due to the asymmetric vibration of the PO2 groups on Q2 tetrahedra. When x > 0.33 the isolated Cu-octahedra begin to share common oxygens to form a sub-network in the phosphate matrix. The effects of glass structure on the glass properties, including density, refractive index, and glass transition temperature, are discussed.