Interaction of microstructure development with viscous flow processes in glass

Abstract Measurements in glasses undergoing phase separation showed a large increase of viscosity with heat-treatment time. A correlation of this effect with electron micrographs of the structure indicated that the change in viscosity was related to an increase in size of the microstructure. A theoretical analysis is presented which is based on a model relating point-to-point variations in molecular environments to viscous flow processes in glass.