Structural study of molten pseudo-binary B2O3‒Na2O · 2SiO2 system by X-ray diffraction and molecular dynamics simulation

Structural investigation of five molten samples of the pseudo-binary B₂O₃{single bond}Na₂O · 2SiO₂ system has been made using both X-ray diffraction and molecular dynamics simulation. The molecular dynamics simulation on more than 1000 atoms, assuming the pair interactions of Born-Mayer-Huggins form, was found to reproduce the experimental interference function and its compositional dependence within reasonable uncertainties. By comparison of the experimental and simulated results, the actual liquid is expected to have a network structure composed of SiO₄^4-, BO₃^3-, and BO₄^5- units. The distributions of neighboring B and Si ions are estimated by the simulation to be almost at random. The experiments for glassy samples have also been carried out, but there is no essential difference in the local ordering structures of molten and glassy states.