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(η, 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.