ASTM C1350 – Standard Test Method for Measurement of Viscosity of Glass Between Softening Point and Annealing Range (Approximately 108 Pa·s to Approximately 1013 Pa·s) by Beam Bending (Metric)
Significance and Use
4.1 This test method is well suited for measuring the viscosity of glasses in ranges higher than those covered by parallel plate (see Test Method C1351M) and rotational viscometry (see Practice C965) methods. This test method is useful for providing information related to the behavior of glass after it has been formed into an object of commerce and in research and development.
1.1 This test method covers the determination of glass viscosity from approximately 108 Pa·s to approximately 1013 Pa·s by measuring the rate of viscous bending of a simply loaded glass beam.2 Due to the thermal history of the glass, the viscosity may not represent conditions of thermal equilibrium at the high end of the measured viscosity range. Measurements carried out over extended periods of time at any temperature or thermal preconditioning will minimize these effects by allowing the glass to approach equilibrium structural conditions. Conversely, the method also may be used in experimental programs that focus on nonequilibrium conditions.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.