Compositional, temperature, and pressure controls on structural order, dynamics, and properties of multicomponent borosilicate glasses

Stanford University, Stanford CA

Investigators

Abstract

NON-TECHNICAL DESCRIPTION Borosilicate glasses are widely used in technology, with applications ranging from heat- and chemical-resistant glassware and reaction vessels, to reinforcement fibers in 'fiber-glass', to computer, television and smart phone display screens and solar-cell substrates. Many of these are central to multi-billion dollar U.S. industries. The atomic-scale structure of these materials controls their properties, which must be tailored to improve performance in their diverse uses. This project seeks to understand general principles of how variations in the glass composition, the way that it is heat-treated during manufacturing, and the pressures that can occur during bending and cracking, change the glass structure, to allow desired properties to be more easily predicted and engineered. The results of these studies should have more general interest as well, in other fields of science where glasses (and the liquids that form glass on cooling) are important, including geosciences and condensed-matter physics. Education is central to this project, since most of the research will be undertaken as part of the training of graduate and undergraduate students on their ways to careers in science and engineering. TECHNICAL DETAILS In this project, the professor and his students are synthesizing several series of glasses with systematic variations in composition, and then measuring how the glass structure changes. The most important experimental approach that is being used is solid-state nuclear magnetic resonance (NMR) spectroscopy, which provides quantitative details about the structure around many of the components common in technological glasses, including boron, aluminum, silicon, and oxygen. By varying the thermal and pressure treatments of the glasses, they can look for important, but still poorly-understood, effects. They are analyzing their findings with thermodynamic-based reaction equilibria to facilitate prediction of properties. Effects of 'non-traditional' components with unusually small and/or highly charged cations are being emphasized. Much of the current development of improved and new types of glass materials comes from trial-and-error experimentation; thus, it is an important goal to develop more fundamental understanding of structure-property relationships to efficiently explore parameter spaces. Success with this goal could lead to more effective ways of thinking about designing glass compositions for new or specific applications. Given the major efforts in glass science in other countries, and the importance of manufacturing high-tech glasses in U.S. industry, it seems particularly urgent for US-based researchers to make progress in the more fundamental understanding of these materials and remain as leaders in this field.