SPECTROSCOPIC STUDIES OF SOME PHOSPHATE GLASSES WITH MANGANESE IONS

D. Toloman1, C. Tripon1, I. Bratu1, O. Raita1, L. M. Giurgiu1 and I. Ardelean2

1National Institute for Research and  Development of Isotopic and Molecular Technologies, P.O. Box 700, R-400293, Cluj-Napoca,Romania
2Faculty of Physics, Babes-Bolyai University, R-400084, Cluj-Napoca, Romania

The structure of yMnO(1-y)[xP2O5CaO] glass system with 1  y  5 mol % and  x = {1; 1.5; 2; 2.5; 3} was investigated by IR and EPR spectroscopy.
IR spectra of the yMnO(1-y)[xP2O5CaO] glasses exhibit the characteristic bands for phosphatic glasses because of the low MnO contents. The frequency ranges of the observed infrared bands belonging to (PO4)3- and (P2O7)4- groups are discussed. The intensity and frequency variations for the characteristic phosphate group vibrations: P-O-P bending and stretching, P = O stretching have been correlated with the changes of the structural units present in these glasses.
EPR spectra of these glasses have been recorded in the X-band (9.3 GHz) at room temperature. All the investigated samples exhibit resonance signals, which are characteristic to the Mn2+ ions. The shapes of the EPR spectra are also changed with the increasing of manganese ions content. This fact may be explained by the superposition of the EPR signals, one with a well-resolved hyperfine structure, typical for isolated Mn2+ ions and the other one consisting in a broad line without hyperfine structure, characteristic for cluster Mn2+ ions.
Both IR and EPR investigation on yMnO(1-y)[xP2O5CaO] glass system inform about the structural effect of MnO on the calcium-phosphate glass matrix.