Measurements on the thermal expansion of fused silica

Abstract

This paper gives the results of an investigation on the thermal expansion of transparent and nontransparent fused silica for various temperature ranges between-125 and +1,000° C. A total of 48 expansion tests were made on 17 samples of fused silica. A detailed description of the apparatus and the methods used in this research and a summary of available data obtained by previous observers on the thermal expansion of fused silica are given. A critical temperature or minimum length was found at about-80° C. Expansion occurred on heating fused silica above the critical temperature or cooling below this temperature. The coefficients of expansion of the transparent samples dififer slightly from the coefficients of the nontransparent samples. Typical expansion curves are shown and discussed. The authors' average expansion curve is compared with the results of previous investigators. The table in the summary gives a r6sum^ of average coefficients of expansion derived from the data on all samples for various temperature ranges between 20 and 1,000° C.