ISO 7884-7:1987

Glass — Viscosity and viscometric fixed points — Part 7: Determination of annealing point and strain point by beam bending

The specified method provides values being useful for specifying the cooling programme in the production of glassware. The annealing point is determined by measuring the rate of midpoint viscous bending of a simple loaded glass beam. The strain point is subsequently determined by an extrapolation method. Annex A provides the formulae for cross-sectional moment of inertia at various cross-section geometries, and annex B shows an example of beam bending apparatus