Application of Dielectric Mixtures Formulae to PbTiO3 Based Glass-Ceramic Systems

Glass samples with composition (50 - X) PbO - (25 + X) TiO2 - 25 B2O3 (where X =0, 5, 10 and 12.5 mol %) were prepared using conventional quenching technique. These glass samples were converted to glass ceramics by following two stage heat treatment schedules. Transition temperature (T-g), crystallization temperature (T-c), density and Coefficient of Thermal Expansion (CTE) of glass and glass ceramic samples measured. T-g and T-c observed to decrease with increase in the content of TiO2. The density values of glass ceramic samples are higher than those of corresponding glass samples. It was observed that there was good correlation between the density and CTE results of the glass-ceramics. The dielectric constant of glass ceramic samples is higher than those of corresponding glasses. Maxwell's dielectric mixture formula was used to correlate the theoretically predicted values of dielectric constant with experimentally observed values.