Glass formation in K2SO4-CaO-P2O5 system

The glass forming region in K2SO4-CaO-P2O5 ternary system is identified, the coefficient of thermal expansion, glass transition temperature and refractive index of the synthesised glasses has been determined and the respective contours are plotted in the ternary diagram. These glasses possess low refractive index, glass transition temperature and high thermal expansion coefficient. Infrared spectroscopic studies on these glasses confirm the Presence of sulphate along with phosphate units in the glass network. Sulphate-phosphate glass is considered to be made up of ultramicroscopic clusters of sulphate rich and phosphate rich units with potassium and calcium ions residing in tetrahedral voids created by four sulphate or phosphate units in contact with each other. These clusters are interconnected by a tissue like texture of average composition. The high field strength of calcium ions brings nonbridging oxygens closer and makes the glasses more compact