A New Approach to the Study of the Viscosity of Glass in and below the Annealing Range

JSGT 1951 V35 T490-T496

Apparatus has been designed, and is now described, for the determination of the viscosity and the flow characteristics, under known loads, of specimens of glass of fairly large size at temperatures below the softening point. For a glass of the approximate percentage composition SiO₂ 72, R₂O₃  l·5, CaO + MgO 12, Na₂O + K₂O 14·5, the viscosity at 525° was logη=14·35. Preliminary results for the temperatures 448° and 400° are quoted.

G. M. Blaimont, J. R. G. De Bast, P. G. Migeotte & H. P. C. Vandecapelle