EPR investigations of calcium phosphate glasses containing manganese ions

Glasses of the xMnO·(100−x)[yP2O5·CaO] systems, with y=1, 2, 3 and 0≤x≤50 mol% MnO were prepared and investigated by means of electron paramagnetic resonance (EPR). The local order in diamagnetic vitreous matrices could be revealed by the Mn2+ paramagnetic ions used in EPR experiments. In each systems corresponding to a particular value of y, the effect of increasing the MnO content in the samples was investigated. The structure of our glasses shows an evolution depending of MnO content from structural units involving Mn2+ ions in well defined vicinities, to structural units containing clustered manganese ions. The changes of the linewidth and the intensity of the resonance line centered at geff≈2.0 when the content of manganese ions are increasing revealed this evolution.