Flow Via Dislocations In Ideal Glasses.

Dislocation lines with variable Burgers vectors can exist in glasses and there is now experimental evidence for this, especially in metallic glasses. The kinetics and dynamics of their motion is discussed. It is suggested that dilatance at the core of a moving dislocation determines the viscous drag that acts on it in an ideal glass; and this is discussed in terms of free-volume theory. Defect debris in the wake of a moving dislocation is also considered. The advantages of using dislocation theory for describing the flow of glasses are outlined.