U.S. and European researchers say they've come up with a method to improve the strength of glass, which could lead to more durable display screens, windows and fiber optic cables.
Engineers at UCLA, working with colleagues at the Université Pierre et Marie Curie in Paris, used computer simulations to analyze the molecular dynamics of materials commonly used to make glass.
Their study identified a range of pressures best suited to achieving "thermal reversibility" in a material, defined as the ability to retain the same properties it possessed when it was produced, even when exposed over time to constant variations in temperature.
Glass is technically a liquid that is cooled during the manufacturing procedure to an almost stable "frozen liquid" state, but as glass ages and undergoes temperature variations, flow will continue and the glass will "relax," causing a change in its shape, the researchers explain.
As a result, glass in windows or display screens can eventually deform and finally become unstable.
The process is similar in concrete, which possesses a molecular structure very much like glass, and such relaxation can eventually result in cracking and the loss of structural integrity in tall buildings and long bridges, the researchers point out.
Mathieu Bauchy, a UCLA professor of environmental and civil engineering, and materials scientist Matthieu Micoulaut at the French university, set out to find the optimal conditions that would create stronger glass and cement.
"The key finding is that if you use specific conditions to form glass -- the right pressure and the right composition of the material -- you can design reversible glasses that show little or no aging over time," Bauchy says.
Those specific conditions improve the angles at which molecular bonds in the material occur, Brauchy says, comparing it to the way the steel beams and crossbeams meet in a structure such as the Eiffel Tower to give it inherent strength.
In addition to creating stronger glass and cement, the improved process could exert a significant effect in reducing emissions of greenhouse gases, the researchers say.
For instance, the production of concrete and cement presently accounts for around 5 percent of all greenhouse gas emissions, according to the American Ceramic Society.
Stronger glass or cement means less material would be needed to yield the same overall strength in a structure of product, Bauchy says.
"The smaller the quantity of material we use to rebuild deteriorating structures, the better it is for the environment," he says.
