Composition-structure-properties relationship of lithium-calcium borosilicate glasses studied by molecular dynamics simulation

The composition-structure-properties relationship of the lithium-calcium borosilicate (LCBS) glasses, which have a composition of 0.4[(1-x)Li2O-xCaO]-0.6[(1-y)B2O3-ySiO2] with x in the range of 0-1 and y in the range of 0.33-0.83, is investigated by the molecular dynamics (MD) simulation with the Buckingham potential. The structure of the silicon-oxygen tetrahedron is relatively independent of the glass compositions; however, the structure of the boron-oxygen polyhedron and the local environment around the modifier cations change significantly with increasing [SiO2]/[B2O3] ratio (K) and CaO content. The relationships between glass composition and simulated linear thermal expansion coefficient (αL), glass transition temperature (Tg), self-diffusivity (D), activation energy of electrical conductivity (Eaσ) and fragility (m) are strongly affected by the change of glass network structure, and consistent with those of experimental results.