ISO 6760-2:2024 PDF

This document specifies a test method for the temperature coefficient of refractive index of optical glass using interferometry. Temperature changes in optical glass lead to changes in the optical path length. The change in optical path length can be measured with an interferometer using the number of cycles of light/dark change of the interference stripe. This document defines a test method to measure the amount of change in the refractive index when the temperature of the specimen is changed continuously. The intended temperature range for the specified measurement method is an arbitrary range. The intended wavelength range for the specified measurement method is 365 nm to 1 014 nm. The intended accuracy for the specified measurement method is within 1 × 10-6 K-1.