Optical and structural properties of Mn2 + doped PbGeO3–SbPO4 glasses and glass–ceramics

• Optical and structural properties of Mn2 + doped PbGeO3–SbPO4 glasses were investigated.
• Glass–ceramics were prepared by thermal treatment.
• Optical properties were monitored in-situ during the thermal treatment using UV–Vis spectroscopy.
• Two distinct crystalline phases were observed after crystallization.

This paper shows the study of optical and structural properties of SbPO4–PbGeO3–MnCl2 glass and glass–ceramics. Glass was prepared by melting–quenching methodology while the glass ceramic was obtained by controlled thermal treatment of the glass. The UV–Vis results show that the glass presents only Mn2 + species, but, the thermal treatment leads to oxidation of Mn2 + to Mn3 + species, what was evidenced by an absorption band in the visible range. High resolution transmission electron microscopy shows the presence of nano-crystalline phases of Mn2O3 and PbGeO3 confirming the formation of a glass–ceramic. Electron paramagnetic resonance measurements suggest that manganese ions occupy only one environment in the glass. On the other hand, for glass–ceramic at least three different structural sites were identified by simulation of the EPR signal.