Enhancement of structural and optical properties of transparent sodium zinc phosphate glass–ceramics nano composite

Transparent sodium phosphate glass–ceramics system according to the composition (55-x) P₂O₅.(30 + x)ZnO.15Na₂O where x = 0, 2.5, 5, 7.5, and 10 was prepared with the melt quenching technique. Different techniques such as XRD and infrared spectroscopy (FTIR) were used to investigate the structure of the studied glass samples and glass–ceramics nano composite. XRD revealed the formation of crystalline phase. The crystalline phase of Na₂Zn (P₂O₇) and Na₂ZnP₂O₇.Zn₂P₂O₇ has been detected which varies according to the ZnO concentration. The density increased whereas molar volume decreased as ZnO content was increased. Optical band gap values, direct and indirect, decreased with increasing ZnO content revealing that bridging oxygen linkage Zn–O-P present in the glass network. The band gaps were found to be ranging between 3.42 and 3.13 eV for indirect transition and ranging between 4.34 and 4.20 eV for direct transitions. It was concluded that the samples have a strong tendency to be crystallized with increasing ZnO content in the sample. This crystallization behavior with increasing the ZnO content affected the structure and optical properties of the prepared samples. In this work, a low cost, wide band gap transparent ceramic with wide range of transparency was prepared and investigated. Such glass–ceramic system is suitable for doping with rare-earth element and/or transition metals for laser and optical devices.