The Temperature Variation of Thermal Expansion and Electrical Resistivity of a Borosilicate Glass

JSGT 1951 V35 T103-T135

Measurements of the thermal expansion and electrical resistivity of “Pyrex” Chemical Resistant Glass have been made over a wide range of temperature. For the expansion measurements two techniques were adopted. The first, for temperatures below the annealing range, was used to measure instantaneous change of length corresponding to a sudden temperature change and also subsequent length change during stabilisation at the new temperature. The second technique was for temperatures somewhat above the annealing range, where stabilisation is rapid and where the chief practical difficulty lies in correcting for viscous flow. The electrical-resistivity measurements were carried out at high temperatures and then, by the use of a continuous-recording technique, were extended into the annealing range. Corresponding to an applied temperature change, values for the instantaneous resistivity change and changes during stabilisation were determined. The rate at which stabilisation occurred was found to have a linear relationship with the reciprocal of the absolute temperature in very close agreement with that obtained from the expansion measurements.

S. M. Cox, J. F. Stirling & P. L. Kirby