Conical-Indenter Penetration Viscometry on Thin Glass Plates

A method is proposed for calculating the viscosity of glasses from the rate of penetration of a conical indenter into thin samples with a thickness of 0.11–4.00 mm under conditions of continuous heating at a rate ranging from 1 to 10 K/min and an indenter loading in the range from 300 to 20 g. This method makes it possible to measure the viscosity of glasses in the range 10¹²–10⁷P for samples in the form of plates 0.13–0.18 mm thick with an error of no more than ±0.2log(, P). The described variant of the indentation method requires the preliminary calibration against a reference (standard) glass; i.e., it is a relative method. This method can be successfully used for determining the viscosity of easily crystallizing glasses.