Some aspects of the visco-elasticity of glass and its structure
JSGT 1957 V41 T095-T116
The rheological properties of glass are discussed and an attempt is made to deduce the real behaviour of these properties at temperatures up to and above the transformation range. It is suggested that a delayed elastic deformation will give a sigmoidal curve when S/S0 is plotted against logt, but that, as at room temperature only the first 'tail' of this curve is involved, this relationship appears to be linear. At higher temperatures the 'peak' in the relaxation spectrum results in behaviour of a more nearly exponential character represented to some degree by quite a different equation, namely, logS/S0=at. A qualitative explanation of the processes in terms of the variation of potential within the glass structure is suggested, and the reversibility of some ionic movements is ascribed to the existence of a certain type of potential well. The phenomenon of 'stabilisation' is also considered in this light. The overall temperature variation of four common viscoelastic parameters is given.
P. L. Kirby
