4.1 This test method is well suited for measuring the viscosity of glasses between the range within which rotational viscometry (see Practice C965) is useful and the range within which beam bending viscometry is useful (see Test Method C1350M). It can be used to determine the viscosity/temperature curve in the region near the softening point (see Test Method C338). This test method is useful for providing information related to the behavior of glass as it is formed into an object of commerce, and in research and development.

1.1 This test method covers the determination of the viscosity of glass from 10⁴ Pa·s to 10⁸ Pa·s by measuring the rate of viscous compression of a small, solid cylinder.2

1.2 The values stated in SI units are to be regarded as the 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.