Structural Changes and Molecular Mobility during Physical Ageing of Glasses
نویسندگان
چکیده
The magnitude of secondary relaxation and heat capacity of a variety of glasses decrease on physical ageing. The decrease suggests a collapse of localized high-volume, highentropy regions in its structure. Densification on ageing affects the kinetic, vibrational and electronic properties of a glass differently than does densification on compression. Tunneling centres responsible for the low-temperature behaviour of glasses are identified with the localized regions. Ageing causes a glass to approach a structure with properties of an isotropic elastic continuum. The results support a microscopically heterogeneous structure.
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