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)
The viscosity of glass from 10 to 15 Poise (log10) is determined by measuring the rate of viscous bending of a loaded glass beam. Representative specimens, nominally 3 to 4 mm in cross section and 75 mm in length, are required.
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 10 13 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 non-equilibrium 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.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Extracted, with permission, from ASTM C1350M 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), copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the standard may be purchased from ASTM International, phone 610-832-9555, e-mail: firstname.lastname@example.org, website: www.astm.org.
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