Cooperative relaxation processes in glass forming polymers and non-polymers

Abstract

The conformational relaxation near the glass transition is a local intermolecular cooperativity phenomenon. As the temperature is lowered, the domains of cooperativity grow in size toward the infinite size but never reach it. The relaxation function is derived from the distribution of domain size according to the equipartition principle. It fits data better than the KWW equation, particularly at high frequencies. This distribution implies that a significant number of conformers continue to undergo liquid-like (picosecond) relaxation even near the glass transition temperature.<>