HIGH-TEMPERATURE ANNEALING EFFECTS ON THE AC CONDUCTIVITY OF SWEPT SYNTHETIC QUARTZ

The effect of prolonged annealing treatments at elevated temperatures (900-1700 K) on the a.c. ionic conductivity of Sawyer PQ 'hydrogen swe pt' quartz has been investigated by impedance spectroscopy measurement s. Transient and irreversible effects have been observed during the an nealings: specifically, a monotonic enhancement of the conductivity is detected in the 900-1300 K temperature range, while at higher anneali ng temperatures an opposite effect is evidenced. The experimental resu lts can be interpreted in the frame of a phenomenological model featur ing two equilibrium reactions; an indirect role of hydrogen impurity i n the ionic transport dynamics is evidenced, also by means of infrared spectroscopy measurements.