Interpretation of glass transition phenomena in the light of the strength-fragility concept

✍ Scribed by Hutchinson, John M.

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 278 KB
• Volume: 47
• Category: Article
• ISSN: 0959-8103
• DOI: 10.1002/(sici)1097-0126(199809)47:1<56::aid-pi996>3.0.co;2-y

✦ Synopsis

The use of a phenomenological model to describe relaxation in the glassy state is reviewed, and it is shown that many important glass transition phenomena may be interpreted in this way. The key parameters of the model (the non-linearity parameter x, the non-exponentiality parameter b, and the apparent activation energy *h*) are discussed in terms of their inÑuence on these phenomena and, more particularly, on the relationship between relaxation in the nonequilibrium glassy state and the strength/fragility of the corresponding equilibrium melt behaviour. Good correlations between these parameters are shown, on the basis of which one can associate fragile behaviour with a high degree of non-linearity, a wide distribution of relaxation times and a large apparent activation energy. However, strong behaviour, which may be associated with a relatively linear response, a narrow distribution and a smaller apparent activation energy, can be characterized by continuity between melt and glass as the transition region is traversed on cooling.