Molecular dynamics of the Na₂O - MgO - CaO - SiO₂ glasses

Abstract

Glasses of the following compositions were prepared by means of molecular dynamics simulation: 0.15 Na₂OxMgO(0.1-x) CaO*0.75 SiO₂, x=0, 0.02, 0.04, 0.06, 0.08, 0.10. The influence of the replacement of Ca ions with Mg ions on the short- and medium-range structure was studied and discussed in frame of radial distribution functions, coordination numbers, and Q-species. Results are compared with Q-distribution obtained by means of Raman spectroscopy. High content of sodium oxide produces itself such abundant amount of non-bridging oxygen atoms that alkaline earth oxide cations Charge balancing requirements are fully saturated and the MgO/CaO Substitution does not change the glass structure in frame of Q-units.