Verre — Viscosité et points viscosimétriques fixes — Partie 7: Détermination de la température de recuit et de la température de contrainte par flexion de barreau

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