The effect of SnO and PbCl2 on properties of stannous chlorophosphates glasses

The effect of PbCl2 or SnO addition on properties of stannous chlorophosphate glasses has been studied. Either SnO or PbCl2 addition improves chemical durability of these glasses in deionized water. Density, hardness, glass transition temperature and softening temperature of the glasses increase with increasing PbCl2 or SnO content. Crystallization of a 40P(2)O(5)-50SnCl(2)-10PbCl(2) glass appears at a temperature around 440 degrees C with an activation energy of 271 kJ mol(-1). Fourier transform IR spectra indicate the presence of Pb-O-P linkages and P-Cl bonds in the short-range glass structure, -[PClO3]-tetrahedron. A possible structural model of Sn-Pb-P-O-Cl glasses is proposed and used to explain the property change due to composition variation. The effect of prolonged melting for 30-60 min on the properties and spectroscopy of Sn-Pb-P-O-Cl glasses is subtle.