Evolution of structure and properties in oxyfluorogallate glasses upon incorporation of Al³⁺ ions

Abstract Oxyfluorogallate glasses exhibit remarkable mid‐infrared transmission properties, making them ideal for various advanced applications, such as environmental monitoring, gas sensing, space communications, and biomedical diagnostics. However, thermal instability, poor moisture resistance, and poor mechanical strength hinder the development and application of oxyfluorogallate glasses. In this research, by progressively replacing Ga 2 O 3 with Al 2 O 3 , the optimized glass system exhibits remarkable thermal stability with a glass transition temperature window (Δ T ) reaching 205°C. This significantly improved chemical durability evidenced by normalized elemental leaching rates reduced below 80% of oxyfluorogallate and superior mechanical properties, including a Knoop hardness of 643.4 kg•N/mm 2 and bending strength of 124.5 MPa, which is comparable to the level of quartz glass.