Preparation and properties of SnO–SnCl2–P2O5 glass

The glass forming region in the ternary system SnO–SnCl2–P2O5 has been determined. Glass transition temperature (Tg), dilatomeric softening temperature (Ts) of the glass, and the viscosity of the liquids in the binary SnO–P2O5 and SnCl2–P2O5 systems were measured. Compositional dependencies of these properties have been investigated. The Tg and Ts of the glasses and the viscosity of liquids for the SnO–P2O5 glasses increase linearly with increasing SnO content in a range of 40–60 mol% SnO. The substitution of chlorine for oxygen by increasing the SnCl2/SnO ratio results in a decrease of Tg and Ts of the glasses and the viscosity of the liquids. The Tg and Ts of the glasses and the viscosity of the liquids of the SnCl2–P2O5 system increase between 40 and 60 mol% SnCl2, are a maximum at about 60 mol% SnCl2, and then decrease with further addition. The SnCl2–P2O5 systems had a decreasing viscosity, which is not observed in the SnO–P2O5 and SnF2–P2O5 systems. The 70SnCl2–30P2O5 glass, having a viscosity between 0.4 and 10 Pa s in a temperature range of 500–600 K, would be useful in a practical application for sealing glasses.