  Lithium disilicate glasses and glass-ceramics are good potential candidates
for biomedical applications and solid-state batteries, and serve as models of
nucleation and crystal growth. Moreover, these glasses exhibit a phase
separation that influences their nucleation and crystallization behavior. The
atomistic mechanisms of the phase separation and their pressure dependence are
unclear so far. Here, we used molecular dynamics simulations supported by
experiments to assess the spatial heterogeneity of lithium disilicate glasses
prepared under pressure. We show that the glass heterogeneity decreases with
increasing the cooling pressure and almost disappears at pressures around 30
GPa. The origin of the heterogeneity is due to the attraction between Li
cations to form clustering channels, which decreases with pressure. Through our
results, we hope to provide valuable insights and guidance for making
glass-ceramics with controlled crystallization.
