Résumé
Structural and dynamic properties of silicate melts and glasses (SiO
2 and its mixtures with Na
2O and Al
2O
3) are derived from Molecular Dynamics simulations and compared to pertinent experimental data. It is shown that these mixtures exhibit additional intermediate order as compared to pure silica, where the characteristic length scales stem from the tetrahedral network structure. While sodium ions show much faster diffusion through percolating channels than the silicon and oxygen ions forming the surrounding network, aluminium ions are incorporated into the network (leading to tricluster formation) and do not show such an enhanced mobility.