The defect diffusion model and the properties of glasses and liquids

• Published in: Journal of non-crystalline solids 2006-11, Vol.352 (42-49), p.4835-4842
• Main Authors: Bendler, J.T., Fontanella, J.J., Shlesinger, M.F.
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Conductivity; Dielectric properties; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Fragility; Glass transition; Physics; Polymers and organics; Pressure effects; Relaxation, electric modulus; Solid-solid transitions; Specific phase transitions; Transport properties – liquids
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2006.02.176

Several previously unexplained relaxation phenomena are interpreted quantitatively in terms of the defect diffusion model (DDM). These include widely different pre-exponentials, exponents and consequently fragility. In addition, the DDM is used to give a qualitative explanation of many properties that glasses and liquids exhibit. This includes interpretations of the glass transition (Tg), the liquid–liquid transition (TB), the crystalline melting temperature (Tm), and the different values of the characteristic temperature, TC, that some materials exhibit for different types of physical measurements. Next, qualitative explanations of the origin of secondary relaxations such as the excess wing and the β relaxation are given. In addition, the boson peak is discussed in terms of the DDM. Finally, it is pointed out that in the DDM, universality is embodied in the defects i.e. free volume.