Structural characterization of sulphate borophosphate glasses containing calcium oxide

Abstract

Increasing demands for better perfoming glasses have lead to current investigating of the sturctural properties of glasses for optimum performances. Calcium sulphate borophosphate glasses of different compositions were prepared using melt quenching technique. The glass forming ability and stability were checked using Differential thermal analyzer (DTA). Density and molar volume had been evaluated and analyzed. From the results of XRD, the absent of discrete and continuous sharp peaks confirmed the amorphous nature of the glass compositions while the results from both IR and Raman revealed the existence of SO4, BO4, BO3, P-O-P and PO43-. Addition of CaSO4 to borophosphate influenced the conversion of the dominant BO3 groups to BO4 groups. The structure of the samples was mainly based on metaphosphate, diphosphate and BO4 units, which became depolymerized with addition of CaSO4 content. The glass forming ability and thermal stability were found to increase with an increase in the concentration of modifier content. Glass density and molar volume is found to be between 2.146 to 2.314 gcm-3 and 45.794 to 48.880 m3mol-1 respectively. It is observed that the density of glass increased while the molar volume also increased with respect to increase in concentration of CaSO4 in the glass compositions. We analysed our data using different mechanisms and compared the results with previous works. Our findings show that this glass could be beneficial and considered as a good candidate for optical devices applications.