Rings in covalent glass and an evaluation of configurational entropy associated with rings

In this study, Molecular dynamics were utilised to prepare the structure of 5K2O·95SiO2 glass. Algorithms based on the removal of the redundant bonds were used to decrease the number of overbonded atoms. These algorithms were found to be very effective and led to an experimentally comparable amount of overcoordinated silicon atoms what made the topological network of glass more realistic. The decomposition of the established glass topological network into a disjoint and complete set of reflecting ring structures was performed. Configurational entropy was calculated on basis of the ideal mixing of the structural units obtained from the decomposition. This entropy reflected the topology of the rings and consequently of medium range order. The calculated specific heat drop at the glass transition temperature was within the uncertainness of the available experimental data.

► Molecular dynamics was used to prepare glass structure.
► Elimination of the redundant bonds leads to a more realistic topological network of glass.
► Glass network was decomposed into disjunctive rings.
► Configurational entropy of the glass was calculated based on ideal mixing.
► Calculated specific heat drop at glass transition is within experimental uncertainness.