Calculation of Activation Energy of Ionic Conductivity in Silica Glasses by Classical Methods

Abstract

An equation for the activation energy of ionic conduction in silica glasses is developed. The approach uses the classical ideas of ionic crystal theory and elasticity theory. The equation finally derived involves the radius and valence of the modifier ion, the lattice constant of the glass, the electronic charge, the shear modulus, and three arbitrary parameters. Two of these parameters are shown to be related to the geometry of the silica network and are exactly determined from difiusion of gases in glass data. The other parameter is shown to be approximately numerically equal to the dielectric constant.The theory is compared with the experimental results of 140 glass compositions.

Ionic Conductivity of Mixed Glass Former 0.35Na2O + 0.65[xB2O3 + (1 – x)P2O5] Glasses

“…Although several models exist for the calculation of the activation energy, ΔE a , for ionic conduction in oxide glasses, the Anderson Stuart (A−S) model is the most easily related to the accepted definition of the ionic conductivity, as discussed above, σ = nZeμ. On the basis of the ideas of ionic crystal theory and elasticity theory, Anderson and Stuart 36 proposed that the activation energy consisted of two parts, the binding energy and the strain energy, eq 6 below. Their binding energy…”

“…It was also found that there is no correlation between the percolating accessible volume (volume available for sodium ion movement under the hard-sphere constraints of the model) and the activation energy of the ionic conductivity, suggesting that changes in the free volume available to the conducting ion may not be strongly influential to the activation energy. The ionic conductivity models of Anderson and Stuart 36 have been combined with our experimental ionic conductivity data to develop an atomiclevel understanding of the positive MGFE in the Na + ion conductivity in these Na B P O glasses. In our model, we are able to show that the volumetric contributions are small and do not strongly influence the ionic activation energy, whereas the columbic contributions to the total activation energy are much larger and are the dominant cause of the MGFE in these glasses.…”

Elastic models for the non-Arrhenius viscosity of glass-forming liquids

“…Anderson-Stuart model for ion conduction in glass. 29 These authors argued that the barrier to be overcome for an ion jumping between two minima has two contributions: The electrostatic attraction between an ion and its neighbouring non-bridging oxygen atom and the elastic work needed for the ion to expand the structure during the jump. The latter contribution was estimated using solid-state elasticity theory, leading to Eq.…”

Trends in Effective Diffusion Coefficients for Ion-Exchange Strengthening of Soda-Lime-Silicate Glasses

“…This is what leads to the postulated creation the mentioned paths of mobility. There are various models that aim to describe transport properties in glasses, including the strong electrolyte approach (Anderson and Stuart, 1954) or the weak electrolyte approach (Ravaine and Souquet, 1977). Despite their disadvantages (Martin and Angell, 1986), these models provide a decent understanding that by changing the glass composition (e.g., through introduction of Al2O3, B2O3, and/or P2O5), the number of NBOs is varied.…”