Glass is a versatile material used in a wide range of applications, from light bulb casings to optical fibers. Recently, high-strength glass has become an important focus of materials research, as new technologies demand materials with greater mechanical performance and reliability. However, conventional chemically strengthened glass has several limitations. Chemical strengthening relies on ion exchange at the glass surface, which limits the minimum glass thickness and generates alkali waste that poses environmental and resource challenges. Although high-elastic-modulus oxide glasses have been produced using aerodynamic levitation and laser-heating techniques, these approaches are not suitable for industrial manufacturing because they limit the size of the glass that can be produced. Despite extensive global analysis of glass compositions, no new toughened oxide glass produced by conventional industrial processes has been reported to date.
In industrial glass manufacturing, oxide glasses fabricated using conventional melt-quenching methods are strongly preferred. High Young's modulus values can be achieved using compositions containing rare-earth elements or Ta2O5, which exhibit high bond dissociation energies. Meanwhile, a relatively low glass transition temperature (Tg) is desirable for efficient shaping and reduced environmental impact during manufacturing. However, achieving both a glass transition temperature near 700 °C and a Young's modulus exceeding 120 GPa has remained an unexplored region in the compositional design of oxide glasses.
In this study, colorless, optically transparent oxide glass with a Young's modulus exceeding 130 GPa was successfully fabricated by melt-quenching. The resulting glass samples were larger than 3 mm thick and 60 mm in diameter, demonstrating that high-elastic-modulus glasses can be produced using scalable industrial techniques rather than specialized laser-based processes.
The key findings of this study are as follows:
[1] Large transparent oxide glasses with Young's moduli greater than 130 GPa were successfully fabricated.
[2] The high elastic modulus was achieved without chemical or physical strengthening methods.
[3] Differential thermal analysis indicates the potential for drawing fibers with a Young's modulus approximately twice that of conventional glass fibers.
[4] The thermal expansion coefficient is less than 80 x 10−7 K-1 and can be further tuned by adjusting the chemical composition.
[5] The Young's modulus of related glass-ceramic materials may be further improved through controlled crystallization.
The newly developed glass offers a promising pathway for designing novel oxide glasses with high hardness, high elastic modulus, and improved fracture toughness. These properties make the material suitable for a wide range of applications, including electronic devices, optical components, and fiber-reinforced composites.
Importantly, because this glass is fabricated using a conventional melt-quenching process, it can be readily integrated into existing industrial glass manufacturing systems. One potential application is highly elastic thin cover glass, which could be produced without relying on chemical strengthening through surface modification. This breakthrough opens new industrial opportunities and highlights the potential of advanced oxide glass as a high-value functional material.
Author and funding
The author of this study is Dr. Hirokazu Masai from the National Institute of Advanced Industrial Science and Technology (AIST).
This research was supported by Japan Society for the Promotion of Science Grant-in-Aid for Scientific Research (B) (Number 22H01785) and Transformative Research Areas (A) (Number 20H05882).
