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A series of borate glasses with the composition x(SrO) · (50 – x)V2O5 ·0.5(B2O3) where x = 0, 0.1, 0.2, 0.3 and 0.4 were prepared by melt-quenching technique. The non-crystalline nature of the glasses has been established by XRD studies. Room temperature density and DC electrical conductivity of the samples were investigated in the temperature range of 300 K to 443 K. The molar volume and oxygen packing density (OPD) were estimated. The results show that the density, molar volume and OPD decrease with the increasing of SrO mole fraction. The DC electrical conductivity data has been analyzed in the light of Mott’s small polaron hopping (SPH) model and the activation energies were estimated. The conductivity was observed to rapidly fall and activation energy was found to increase when SrO was incorporated into the glass network. This may indicate that Sr+ ions have not contributed to the total conductivity and the observed conductivity may be of polaronic type only, which is due to the hopping of electrons between multivalent states of vanadium. Various small polaron hopping parameters such as small polaron radius, rp, effective dielectric constant, ∈p, polaron band width, J, optical phonon frequency, νo, small polaron coupling constant, γp, density of states at Fermi level, N(EF) were estimated and discussed.

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In the present study, B2O3 glasses doped with Na2O and Fe2O3 was prepared via melt quenching method. The amorphous nature of the samples has been confirmed by the XRD studies. The polaronic conduction for the wide range of temperature and frequency were studied. As temperature increases the dielectric properties found to be enhanced and with increment in frequency they found to be decreased. The high temperature ac conductivity data has been analyzed by Motts small polaron hopping model (SPH). Activation energy passed through maximum and conductivity passed through minimum at 0.20 concentrations of sodium oxide which attributes that the switch over of conduction process, taking place at 0.20 molar fraction of alkali ions from primarily polaronic to ionic in the present series of glasses.