FORMATION AND PROPERTIES OF LEAD CHLOROSILICATE GLASSES

An extensive glassforming region has been determined for the ternary s ystem PbO-PbCl2-SiO2. The thermal stability of these glasses has been studied using differential scanning calorimetry. The glasses exhibit v ery high anionic (chlorine) conductivities and the value of 2.5 x 10(- 5) S/cm at 200-degrees-C found for one glass is believed to be the hig hest reported to date for a chlorine conducting glass. In general, the ionic conductivity and thermal expansion coefficients increase with i ncreasing PbCl2 concentration, while the density and glass transformat ion temperature decrease with increasing PbCl2 contents. The compositi onal dependence of these properties was discussed in terms of possible roles of chlorine ions in the glass structure.