Property–structure evolution in alkali-free boroaluminosilicate glass via B2O3 substitution for alkaline earth oxides

Abstract

Alkali-free boroaluminosilicate glass (AFBG) is widely utilized in electronic display panels and glass fibers due to its superior mechanical properties and thermal stability. The growing demand for high-performance materials capable of withstanding extreme conditions has propelled the development of AFBG. To this end, understanding the relationship between composition, structure, and properties at the atomic level is essential. This study investigates the effects of substituting B₂O₃ for alkaline earth metal oxides (RO) on the properties and structural variations of AFBG using a combination of experimental techniques alongside molecular dynamics simulations. The results indicate that the substitution of B₂O₃ with RO leads to an increase in [AlO₅] and [BO₃] units, resulting in an enhanced polymerized yet more open structure. This structural change is accompanied by a decrease in the coefficient of thermal expansion and glass transition temperature (T_g). Simultaneously, the reduced content of [AlO₄] and [BO₄] units weakens the overall glass network rigidity, leading to observed declines in elastic modulus and nanohardness. Notably, the changes in local coordination environment around Al dominates the overall structural and property variations. These findings provide atomic-scale insights into the structural mechanisms governing the behavior of AFBG.