Molecular dynamics simulations of borosilicate glasses having differing sodium oxide contents were carried out. The generated structure indicated that most oxygen atoms, introduced as Na2O, were consumed by the borate network to convert the BO3 triangles into BO4 tetrahedra. The formation of non-bridging oxygen ions in the silica site occurred during the formation of BO4 tetrahedra with a low rate. At higher concentrations of Na2O, the non-bridging oxygen content suddenly increased. The self diffusion of sodium ions depended essentially upon the temperature, composition (number of Na+ ions) and rate of cooling. The phase separation mechanism in borosilicate glasses could be detected by molecular dynamics simulation, since the environment of B-O, Si-O and B-O-Si could be easily reached.

Diffusion of Sodium Ions in Borosilicate Glasses by Molecular Dynamics Method. Meikhail, M.S.: Zeitschrift für Physik B, 1991, 84[2], 309-13