This part of ISO 7884 specifies a method of determining, by means of rotation viscometers, the dynamic viscosity of glass and, in particular, the viscosity-temperature relationship at any temperature or viscosity within the range of measurement. This covers the ranges of viscosity for melting, refining and working of glass.This method allows for continuous measurements and for measurements under various shearing stresses (i.e. for the determination of flow curves) in order to check whether or not the glass behaves as a Newtonian liquid.Dependent on the particular viscosity-temperature relationship of the glass tested, the viscosity range covered by this method extends approximately from 10 to 10 dPa·s in the tempera-ture range from about 1 600 to 600 ? the torque necessary ranging from 0,1 to 20 N·mm according to the construction of the apparatus. The method is applicable if the rotational fre-quency does not exceed 8 s; however, at rotational frequen-cies above 1 s it should be ascertained that inertia forces are negligible.note:* 1 dPa·S = 1dN·s/m= 1 P(P is the symbol for poise)