ISO 7884-4:1987 (R2020)

A method of determining the dynamic viscosity of glass on a rod-shaped test specimen, i.e. a beam, supported at its end is specified. The viscous deflection rate of the beam is measured under given load at the midpoint between the supports. In addition the viscosity-temperature relationship and the dependence of the viscosity on the thermal history of the sample can be determined. The theoretical basis relations and the apparatus including method of measurements are described.