MOLECULAR-DYNAMICS STUDY OF GLASS-FORMATION IN THE LI2SIO3 SYSTEM

A molecular-dynamics simulation is carried out to study the changes in statistical geometry and related dynamical properties in the Li2SiO3 system at the glass transition point. The number of oxygens around each cation within the first coordination shell is taken as the number V of vertices of the polyhedron that characterizes the system. When the number N of O-O pairs that are shorter than Ro (Ro, is the position where the second plateau of the running coordination number no-o(r) ends) is counted, the distribution of N is found to have a maximum at N = 3V-6 (V = 3,…, 7) below the glass transition temperature. N corresponds to the number of contact pairs in each polyhedron. The lifetime of the polyhedron with N = 3V-6 is found to be longer than other polyhedra with other values of N. The results suggest that geometrical degrees of freedom play an important role in glass formation in this system. © 1990 Taylor & Francis Ltd.