DIELECTRIC BEHAVIOR AND AC CONDUCTIVITY OF SODIUM-BORATE GLASS CONTAINING COO

Sodium berate glasses of composition (Na2B4O7)(100-x)(CoO)(x), with x = 0, 3, 5 and 7 mol%, were prepared by melting oxide mixtures in a pla tinum crucible at 1050 degrees C in an electric furnace in air for 2 h , and then quenching in air. The IR spectra, AC conductivity and diele ctric behaviour of the quenched glasses are the subject of the present work. Properties such as dielectric constant, loss factor tangent and electrical conductivity as a function of frequency and temperature ar e reported. The AC conductivity is proportional to omega(s) and increa sed as cobalt content was decreased. The value of the exponent (5) dec reased with decreasing CoO content. From the IR spectra, it was found that increasing CoO does not seem to introduce any new absorption band . Also, the activation energies for AC conductivity and the activation energies associated with the relaxation process for different glass s amples are calculated. (C) 1998 Elsevier Science Ltd. All rights reser ved.