Structural Regularities Discovered Within Silica Glass

Despite its ubiquity in terms of usage across many every-day items, glass as a material has always confounded scientists because of its disordered atomic structure. This not only has made understanding and controlling its structural nature challenging, but also made it difficult to design efficient functional materials from glass.

That could change thanks to new discoveries made by a group from Tohoku University in Japan. The team has come up with new ways to classify and identify the ring shapes in chemically bonded networks of glass—part of the structural regularity hidden in glass materials.

Their techniques—which focused on crystalline and glassy silica—revealed that there is both order and disorder in the ring shapes found in glassy materials, something that scientists long have suspected but so far never observed, they reported. 

The discovery could lead to a better understanding of these materials for innovations in their use in material science and design, said Professor Motoki Shiga from Tohoku University's Unprecedented-scale Data Analytics Center, one of the participants in the research.

"The structural unit and structural order beyond the chemical bond had long been assumed through experimental observations but its identification has eluded scientists until now," he said. 

Related:DNA, Glass Used to Create Lightweight Material Stronger Than Steel

Order Among the Glass Rings

Specifically, the research team developed methods to quantify the rings' three-dimensional structure and structural symmetries; that is,  "roundness" and "roughness."

The researchers used these indicators to determine the exact number of representative ring shapes in crystalline and glassy silica, finding a mixture of rings unique to glass and ones that resembled the rings in the crystals. They also developed a technique to measure the spatial atomic densities around rings by determining the direction of each ring.

What the researchers discovered in their observations is anisotropy around the ring shapes found in the glass. In other words, the regulation of the atomic configuration is not uniform in all directions, and the structural ordering related to the ring-originated anisotropy is consistent with experimental evidence, like the diffraction data of silica, they said. 

The researchers also discovered that there were specific areas in the material where the atomic arrangement followed some degree of order or regularity, though it appeared to be a disordered and chaotic arrangement of atoms in glassy silica.

"Furthermore, our successful analysis contributes to understanding phase-transitions, such as vitrification and crystallization of materials, and provides the mathematical descriptions necessary for controlling material structures and material properties," Shiga said.

Related:Origami Inspires Cutting, 3D-Printing Technique for Complex Glass Shapes

Researchers published a paper on their findings in the journal, Communication Materials. They plan to continue their work by using the techniques they developed to create further procedures for exploring glass materials based on data-driven approaches like machine learning and artificial intelligence, they said.