Prof's new theory explains the mysterious nature of glass
Roger Bagula
Interesting Facts
Prof's new theory explains the mysterious nature of glass
Archaeological evidence suggests that glass was first made in the Middle
East sometime around 3000 B.C. However, almost 5,000 years later,
scientists are still perplexed about how glassy materials make the
transition from a molten state to a solid. Richard Wool, professor of
chemical engineering at UD, thinks he has the answer.
In a paper to be published later this year in the Journal of Polymer
Science Part B: Polymer Physics, Wool documents a new conceptual
approach, known as the Twinkling Fractal Theory (TFT), to understanding
the nature and structure of the glass transition in amorphous materials.
The theory provides a quantitative way of describing a phenomenon that
was previously explained from a strictly empirical perspective.
“The TFT enables a number of predictions of universal behavior to be
made about glassy materials of all sorts, including polymers, metals and
ceramics,” Wool says.
What distinguishes glasses from other materials is that even after
hardening, they retain the molecular disorder of a liquid. In contrast,
other liquids--for example, water--assume an ordered crystal pattern
when they harden. Glass does not undergo such a neat phase transition;
rather, the molecules simply slow down gradually until they are stuck in
an odd state somewhere between a liquid and a solid.
Another difference between glasses and more conventional materials is
that their transition from the liquid to the solid state does not occur
at a standard temperature, like that of water to ice, but instead is
rate-dependent: the more rapid the cooling, the higher the glass
transition temperature.
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September 12th, 2008
Source: Udel.edu