Experimental Evaluation of Beam‐Bending Method of Determining Glass Viscosities in the Range 10 ⁸ to 10 ¹⁵ Poises

Abstract

The method of determining the viscosity of a glass by the viscous bending of a simple beam is experimentally compared with the fiber‐elongation technique. For a standard soda‐lime‐silica glass, beam‐bending viscosity data are found to agree well with fiber‐elongation measurements reported by the National Bureau of Standards. An apparatus using the beam‐bending principle is described with which reliable viscosity measurements for glasses are obtained in the range 10 8 to 10 15 poises at temperatures up to 1500°C.