Fundamental Understanding of Dynamical Phenomena Near Glass Transition for Intelligent Design and Processing of Functional Oxide Glasses

University Of California-Davis, Davis CA

Investigators

Abstract

NON-TECHNICAL SUMMARY: From windows and containers to lenses in telescopes and microscopes, innovative developments in the science and technology of oxide glasses (silicates, phosphates, borates, and their various combinations) have been key enablers of civilization throughout history. This strong societal impact of glass continues in the modern times in the form of applications such as optical fibers for long-distance telecommunication and damage-resistant display panels for electronic devices, which have transformed the ways we live and communicate in the modern world. Accelerating the design of these functional glasses to address the grand challenges faced by society requires a fundamental understanding of the underlying relationships between their atomic structure at various length scales and the dynamical processes in their parent liquids, their progression across glass transition along with the temporal evolution of structure-property relationships during physical aging of the derived glasses. This project aims to provide unique and comprehensive knowledge regarding the mechanistic connections between these “microscopic (atomistic)” and “macroscopic” aspects in oxide liquids and glasses for the very first time, using a unique and powerful combination of cutting-edge characterization techniques. Scientifically, this work impacts materials science, physical chemistry, and solid-state physics. The interdisciplinary nature of this work transfers knowledge between fields and provides students with unique opportunities for intellectual growth. Graduates typically find employment in both academia and in glass and semiconductor industry. The impact of this research in education and outreach is in three major areas: (1) engagement of undergraduate and graduate students in cutting-edge research, (2) active collaboration with scientists at multiple National Labs, and (3) disseminating knowledge, especially of glass science and technology, to the broader scientific community. The research findings are embedded into special topics courses that are offered to students in materials science, chemistry, and other related fields; and they contribute to campus programs for the recruitment of promising undergraduate and graduate students. TECHNICAL SUMMARY: Accelerating the smart design of functional oxide glasses to address some of the grand challenges faced by our society today requires fundamental knowledge of the structural relaxation kinetics of supercooled oxide liquids and glasses at length scales extending beyond that of short-range order and of their mechanistic connections with melt fragility, dynamical heterogeneity and physical aging phenomena, which are intimately linked to their viability for various processing techniques utilized in industry. The proposed project will systematically investigate these challenging problems utilizing a uniquely powerful combination of cutting-edge characterization techniques including X-ray photon correlation, NMR, shear-mechanical and electrical impedance spectroscopy and calorimetry to build a comprehensive atomistic understanding of the dynamics and various relaxational phenomena in oxide glasses and deeply supercooled liquids. The results obtained from these studies will provide important and novel constraints for addressing some of the key outstanding questions in glass science, such as the length scale dependence of relaxation and its implications, the nature of the dynamical heterogeneity and its evolution across glass transition and the temporal evolution of structure-property relationships during physical aging. This fundamental knowledge will enable the advancement of predictive models critically needed for optimization of the chemistry and processing parameters of oxide glasses and glass-ceramics for enhanced functionality, thereby permitting their widespread application in transformative technologies with strong societal impact. The breadth, flexibility and interdisciplinary nature of the project will provide the students with unique opportunities of intellectual growth that will open many future career opportunities. It will also enrich the graduate education and training experience through numerous scientific dialogues between the collaborating scientists and participating students. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.