Absolute dilatometry using a polarisation interferometer. II

Abstract

For pt.I see ibid., vol.8, no.7, p.600-2 (1975). An interferometer has been constructed to measure the thermal expansion of solids. The useful resolution is limited to 0.3 nm change in length by the sensitivity of the polarimeter or to about 5 parts in 10⁹ in relative length change by the stability of the laser. Because the divided beams are close together everywhere, the instrument is particularly insensitive to vibration and changes in ambient temperature compared to many other interferometers. No special devices are required to compensate for shear, and readout is completely automatic. Measurements on a sample of titanium silicate glass in the range from -100 to +200 degrees C are reported. Modifications to the sample chamber are expected to extend the operating range to 1500 degrees C.