Properties and structure of copper ultraphosphate glasses

The structures of xCuO (.) (1 - x)P2O5 glasses (0 less than or equal to x less than or equal to 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 Q(3) tetrahedra into a chain-like metaphosphate structure dominated by Q(2) tetrahedra. IR spectra clearly show two distinct Q(3) sites with bands at 1378 and 1306cm(-1), assigned to P=O bonds on isolated Q(3) tetrahedra and P=O 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 P=O band associated with the Q(Cu)(3) tetrahedra increases to a maximum x similar to 0.33, then decreases with a concomitant increase of the intensity of the band at 1265cm(-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.(C) 2004 Elsevier B.V. All rights reserved.