Ionic self-diffusion and the glass transition anomaly in aluminosilicates

Abstract

<p>The glass transition temperature (T_g) is the temperature, after which the supercooled liquid undergoes a dynamical arrest. Usually, the glass network modifiers (e.g., Na₂O) affect the behavior of T_g. However,...</p>

Atomic Structure and Modifiers Clustering in Silicate glasses: Effect of Modifier Cations

“…We could also get an estimate on the degree of ordering in the glass by computing the pair-excess entropy as defined in Ref. [13,34,51]. As shown by the pair-excess entropy (S 2 ), the glass structure becomes more disordered as the FS increases (see Fig.…”

“…In order get some insights into the atomic structure of the glass, we use molecular dynamics (MD) simulations, which is an effective method to help to investigate and understand the atomic-scale behavior of materials and have been applied in studying and oxide glasses [6,7,[34][35][36]. We study the effect of the modifier type on the structural properties of a series of modified silicate glasses were the concentration of the modifiers was fixed to 25 mol%.…”

“…We used on the well-established potential developed by Pedone et al [37]. This potential gives a realistic agreement with available experimental data, as mentioned in the literature [3,7,13,34,[37][38][39][40]. Potential parameters and partial charges are given in the reference ( [37]).…”

Atomistic insights into the mixed-alkali effect in phosphosilicate glasses

“…In this potential, the particles are treated as charge points interacting via Coulomb forces, a Morse function to describe the short-range interactions between pairs of atoms, and an additional r −12 repulsive contribution necessary to model the interactions at high pressure and temperature. This potential gives a realistic agreement with available experimental data as mentioned in the literature [6,17,[22][23][24][25][26] as it was designed to reproduce structural and mechanical properties of a wide range of oxide glasses. Potential parameters and partial charges are given in the Ref.…”

“…It was shown that the modifiers channels play the role of energetically favourable routes for ionic diffusion [30,47]. In oxide glasses, the process of ionic diffusion is composed of a succession of ion hops along the channels, where cation hop from one polyhedron to a recently vacated neighbouring polyhedron [26]. The differences in electronegativity of the alkali metals can also affect the ion release rate, which was observed by the behaviour of the diffusion coefficients and the activation energies.…”