Impact of silver ions on dielectric properties and conductivity of lithium silicate glass system mixed with red lead

Glasses of the composition (40-x)Li2O-10Pb3O4-50SiO2 doped with different contents of Ag2O were fabricated and were subsequently subjected to heat-treatment. The quantitative analysis of the results of different characterization techniques indicated increasing magnitude of internal connectivity of the glass network with increasing Ag2O content. Several dielectric parameters viz., ε′, M, Z and σacin the frequency (ω) region 0.01 Hz – 1 MHz and in the region of temperature (T) 30 –250 °C of these glasses were measured as functions of Ag2O content. ε′ showed a decreasing tendency with Ag2O content which may be attributed to the decrease in the space charge polarization (scp) due to the increasing order of augmentation of glass network. Such a decrease of scp was attributed to the growing presence of PbO4 units and also Ag0 particles in these samples. The plots of electric modulus vs ω and T indicated relaxation character. Such relaxation phenomena were discussed in detail with the help of Cole-Cole diagrams. Probable dipoles responsible for such effects were recognized and analyzed. σac (conductivity) exhibited a decreasing trend with Ag2O content. The mechanism of conduction was analyzed using polaronic tunneling effect in the intermediate ω and high T ranges, whereas in the low T range it is predicted to follow QMT model. These conclusions were observed to follow the results of various spectroscopic studies. In conclusion, presence of red lead seemed to be an obstruction for the conductivity in the fast ion conducting glasses.