Researchers conducted computer simulations to explore how temperature affects molecular dynamics in supercooled glassy liquids. Their findings could lead to the production of higher-quality glass at reduced costs.
While glass is a material we encounter regularly, the underlying physical principles are intricate and not yet fully comprehended by scientists. For instance, some types of glass, like the stained-glass windows found in Medieval architecture, have remained unchanged for centuries because their molecules are perpetually trapped in a disordered state. Similarly, supercooled liquids aren’t completely solid since their particles don’t arrange themselves into a long-range order, but they also aren’t typical liquids, as their particles don’t possess enough energy for free movement. Further investigation is necessary to uncover the complexities of these systems.
In a recent article published in Nature Materials, researchers from the Institute of Industrial Science at The University of Tokyo employed sophisticated computer simulations to analyze how basic particles behave in a glassy supercooled liquid. Their work was grounded in the concept of Arrhenius activation energy, which refers to the energy required to initiate a process. One example is the energy demanded to reorder individual particles in a disordered material. “Arrhenius behavior” describes a process that depends on random thermal fluctuations, where the rate declines exponentially as the energy barrier heightens. In contrast, scenarios needing cooperative particle rearrangements may be less common, especially at lower temperatures, sometimes referred to as super-Arrhenius behaviors.
This study was the first to showcase the connection between structural order and the dynamic behavior of liquids on a microscopic scale. “Using numerical analysis through a computer model of glass-forming liquids, we demonstrated how fundamental particle reorganizations can affect both structural order and dynamic behavior,” explained Seiichiro Ishino, the lead author of the study. The team uncovered that a mechanism they termed “T1,” which preserves the order within the liquid, is crucial for understanding cooperative dynamics. If a T1 process disrupts local order, it must entail the independent movement of particles, leading to standard Arrhenius-like behavior. Conversely, if the T1 rearrangement sustains local order cooperatively, its effects extend outward, resulting in super-Arrhenius behavior.
“Our study offers a fresh microscopic viewpoint on the long-explored origins of dynamic cooperativity in glass-forming materials. We expect these insights will help achieve better control over material dynamics, thus enabling more efficient design and improved glass manufacturing practices,” stated senior author Hajime Tanaka. This could result in stronger, more resilient glass for smartphones and various other uses.
