Dielectric Studies of Some Borate and Phosphate Glasses

Some borate glasses, with sag points of 350° to 500°C., of high specific resistance and low power factor have been prepared. The power factor of the glasses has been measured to 250° C., and the resistivity has been measured up to temperatures approaching the transformation region. Borate glasses have higher resistivities and power factors than phosphate glasses. An increase in sag point of lead borate glasses by substitution of PbO with BaO, Al₂O₃, or SiO₂ improves their dielectric properties. Depending on the type of glass, the dielectric constant varies linearly with the density of the glass.