Measurement of thermal expansivity of low-expansion glasses by interferometric methods: Results of an interlaboratory comparison

Abstract

An interlaboratory testing program on the measurement of the linear thermal expansion coefficient of low-expansion glasses has been carried out. Three different types of interferometric dilatometers, each located at three different organizations, and two kinds of low-expansion glass materials were selected for the experiments. As a result of the comparison, a reasonable agreement among the different measuring instruments was confirmed, and it was determined that the thermal expansion coefficient for low-expansion glasses can be measured with an accuracy of ±4×10−8 K−1 by using commercially available interferometric dilatometers.