‘T_g-Δ Rule’ Applied to Semiconducting Vanadate Glasses Containing Different Amounts of Fe₂O₃

Abstract

‘T_g-Δ rule’, i.e., a linear relationship between the glass transition temperature (T_g) and the Mössbauer quadrupole splitting (Δ), is applied to semiconducting 10K₂O⋅(90-x)V₂O₅⋅xFe₂O₃ and 25K₂O⋅(75-x)V₂O₅⋅xFe₂O₃ glasses (henceforth denominated glass A and B, respectively). Slopes of the straight lines obtained from the plot of T_g vs. Δ (i.e., 685 and 690°C (mm·s^-1)^-1 for glass A and glass B, respectively) imply that the Fe(III) atoms substitute tetrahedral V(IV) or V(V) atoms and play a role of network former. Both T_g and Δ values increase with the Fe₂O₃ content, suggesting that Fe(III) causes an increase in the distortion of VO₄ tetrahedra. Fourier-transform infrared (FT-IR) spectra prove that Fe(III) does not essentially change the network structure. These experimental results are discussed together with the ‘T_g-Δ rule’ that was recently applied to aluminate, gallate and borosilicate glasses.