Glass is getting used in a wider range of high-performance applications, including those for consumers and industry, military and aerospace electronics, coatings and optics. Due to the intense precision demanded to be used in products resembling mobile phones and jet aircraft, glass substrates must not change their shape in the course of the manufacturing process.
Corning Incorporated, a manufacturer of progressive glass, ceramics and related materials, invests an amazing amount of resources into studying the soundness of various kinds of glass. Recently, Corning researchers found that understanding the soundness of the rings of atoms in glass materials may also help them predict the performance of glass products. This capability is significant because probably the most widely used glass is silicate glass, which consists of various sizes of atomic rings connected in three dimensions.
Conducting neutron scattering experiments on the Department of Energy’s Oak Ridge National Laboratory, ORNL and Corning scientists discovered that because the variety of smaller, less-stable atomic rings in a glass increases, the instability, or liquid fragility, of the glass also increases. The outcomes of the neutron experiments, published in Nature Communications, reveal a transparent correlation between the medium-range atomic ring structure of a silicate glass and its liquid fragility. The viscosity of the liquid glass changes considerably when it’s cooled to the glass transition temperature. A more fragile liquid may have a bigger viscosity change with a given temperature change.
“Previously, the mechanism driving glass transitions had eluded scientists,” said Ying Shi, the corresponding creator of the study’s paper and research associate at Corning. “There was no clear understanding as to why some kinds of glass solidified faster or slower.”
Shi and her collaborators from Corning, the University of California, Los Angeles, and the University of Oxford worked with the NOMAD neutron diffractometer beamline scientists at ORNL’s Spallation Neutron Source to check aluminosilicate glass, which is usually utilized by industry.
Using a recently developed and validated neutron scattering data evaluation tool, RingFSDP, the team identified key patterns within the collected data that exposed the connection between the liquid fragility within the glass and its atomic ring stability.
RingFSDP is a free, open-source program developed by Corning and ORNL scientists to check the atomic ring structures of silicate glass. It derives ring-size distributions in silicate glass from the form of the primary sharp diffraction peak within the neutron diffraction data.
“Connecting the glass transition temperature range to underlying structural features of a glass may have a big impact on glass design and production,” said Douglas Allan, the paper’s co-author and a research fellow at Corning. “Our work shows a transparent correlation between the atomic ring structure of a glass and its glass transition temperature range and subsequently the performance features of the glass.”
The study included researchers from the Science and Technology Division at Corning, the Physics of Amorphous and Inorganic Solids Laboratory within the Department of Civil and Environmental Engineering on the University of California, Los Angeles, the Neutron Scattering Division at ORNL’s SNS and the Physical and Theoretical Chemistry Laboratory on the University of Oxford.
