Liquid–liquid phase separation in sodium borosilicate glass: Ordering phenomena in particle arrangement

A structure of 13.9Na₂O · 36.0B₂O₃ · 50.1SiO₂ glass heat-treated at 610 °C for 5 h (glass G1) and 10 h (glass G2) was studied by stereological method on the basis of electron microscopy data obtained from plane sections of samples. It has been found that liquid phase separation in the course of heat treatment leads to formation of spherical particles with the volume fractions 0.047 (G1) and 0.065 (G2). It is argued that the stage of growth takes place in the glass G1 and the Ostwald ripening stage occurs in the glass G2. The analyses of pair correlation functions of particle traces on a secant plane indicate elements of ordering in mutual arrangement of particles for the both glasses G1 and G2. This conclusion is confirmed by results of numerical simulation. The experimental data on the pair correlation functions are in agreement with the results of calculations presented in the literature. It is noted that the ordering elements in mutual arrangement of particles play a key role in light scattering and other physical properties of material.