A model for the viscosity of glass-forming molecular liquids is proposed in which a "flow event" requires a local volume increase. The activation energy for a flow event is identified with the work done in shoving aside the surrounding liquid; this work is proportional to the high-frequency shear modulus, which increases as the temperature decreases. The model is confirmed by experiments on a number of molecular liquids.
|Tidsskrift||Physical Review B. Condensed Matter and Materials Physics|
|Status||Udgivet - 1996|