Impact of chemical composition on mechanical properties and hydrolytic resistance of boroaluminosilicate glasses

Abstract This study investigates the impact of systematic compositional variations on the structure, mechanical properties, thermal behaviour, and hydrolytic resistance of boroaluminosilicate glasses. Network-forming oxides (SiO 2 , B 2 O 3 ), network modifiers (Na 2 O, K 2 O, CaO), and intermediate oxides (ZnO, Al 2 O 3 , BaO) were varied equimolarly. X-ray diffraction confirmed the amorphous nature of all samples. Hydrolytic resistance evaluated by ISO 719 showed differences in extract conductivity (2.2–8.2 µ S cm −1 ), with improved durability for Si+ and Al+ glasses. Density (2.38–2.52 g cm −3 ) and glass transition temperature ( T g = 569–599 °C) have opposite effects on network polymerization, confirmed by Raman spectroscopy. Mechanical testing showed small variations in hardness (5.14–5.28 GPa) and fracture toughness (0.71–0.73 MPa·m 1/2 . The results highlight composition–structure–property relationships that can guide the design of borosilicate glasses with improved mechanical and chemical stability.