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 (T_g), dilatomeric softening temperature (T_s) 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 T_g and T_s 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 T_g and T_s of the glasses and the viscosity of the liquids. The T_g and T_s 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.