Dielectric and Anelastic Effects in Inorganic Glasses

THE dielectric properties of inorganic glasses in alternating fields are usually described in terms of the complex dielectric constant where ε′ is the real part and ε″ is the imaginary part or dielectric loss. The values of ε′ and ε″ are usually obtained from measurements of the capacitance and resistance of a disk shaped specimen fitted with metal electrodes. If the value of C p / C o (where C p is the equivalent parallel capacitance and C o is the capacitance with a vacuum between the electrodes) is plotted against log ω (where ω is the angular frequency), then, in the audiofrequency range and with blocking electrodes (for example, gold or platinum), a curve of the form shown in Fig. 1 is usually obtained with glasses containing appreciable amounts of alkali-metal ions.