A homogeneous 0.08 Rb2O·0.92 SiO2 glass has been tested at temperatures between 480 and 555°C (low-stress viscosities between 1017.1 and 1013.5 poise) and at stress levels up to 109.5 dyne/cm2 or more. At low stress levels, Newtonian behavior was observed; at stress levels above some critical stress, the viscosity was observed to decrease with increasing stress. This critical stress for non-Newtonian flow was found to be about 109.1 dyne/cm2, approximately independent of temperature. The variation of the viscosity with stress in the high-stress region can be described by absolute rate theory only by assuming a flow volume which increases with increasing stress.
ASJC Scopus subject areas
- Ceramics and Composites
- Electronic, Optical and Magnetic Materials