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Spectroscopic investigation on some calcium-phosphate glasses

N. VEDEANU1,* , O. COZAR1, I. ARDELEAN1, S. FILIP2

Affiliation

  1. Babes-Bolyai University, Dept. of Physics, 400084 Cluj-Napoca, Romania
  2. University of Oradea, Faculty of Sciences, 410087 Oradea, Romania

Abstract

Phosphate glasses containing transitional metal ions (TMI) are interesting because of their semiconducting and optical properties and because of their potential applications in solid-state lasers and as optical fibres for communication devices. In order to evidence the structural changes induced by CuO and V2O5 in the phosphate glass network and their modifier or former role, the following two glass systems were prepared and investigated by EPR and Raman spectroscopy: xCuO(1-x)[P2O5.CaO] and xV2O5(1-x)[P2O5.CaO] with 0≤x≤40 mol%. EPR results obtained for copper doped glasses show g║ > g┴ indicating a tetrahedral (Td) site for Cu2+ ions. In the case of vanadium doped glasses, g║ < g┴ and indicates that vanadium ions exist in a square pyramidal (C4v) site as VO2+ ions. The vibrational bands belonging to the phosphate groups appear clearly in the spectra at low concentration of TMI, but at high concentrations these bands are influenced by those belonging to CuO and V2O5 groups; this fact indicates that both oxides act in the phosphate network as modifiers. In the case of vanadium doped glasses, at high concentration of oxide (x>20 mol%) the bands belonging to the vibration of V2O5 groups dominates the spectra while the bands belonging to the phosphate groups are strongly reduced except the specific bands of the short chain phosphate units. From this consideration we can conclude that vanadium prefers to bridge with the oxygen that do not take part in the PO4 units and in consequence it acts as a network former..

Keywords

Phosphate glasses, Transitional metal oxides, EPR, Raman spectroscopy.

Submitted at: Dec. 2, 2005
Accepted at: May 18, 2006

Citation

N. VEDEANU, O. COZAR, I. ARDELEAN, S. FILIP, Spectroscopic investigation on some calcium-phosphate glasses, Journal of Optoelectronics and Advanced Materials Vol. 8, Iss. 3, pp. 1135-1139 (2006)