TEMPERATURE-DEPENDENT AC IMPEDANCE STUDIES OF GLASS TO METAL CONTACTS IN SOLID-STATE GLASS PH SENSORS

Two major types of electrode contact were studied: vacuum evaporated Au, Ag and Cu and thick film-deposited contacts which are fused at high temperature (1000 degree C) and involve Pt, Cu, Fe and their oxides. The frequency dependent ac spectra of the real and imaginary contributions to conduction were monitored over a frequency range 10** minus **4 Hz to 10**6 Hz. Temperatures were varied between ambient and 431 K. The spectral information was studied in both complex impedance and complex admittance forms; these two representations of the same information are used to determine simple equivalent circuits and relevant energies of activation for each relaxation.