SCHOTT Advanced Optics offers an updated datasheet for the optical glass N-FK58 XLD, a high quality optical glass with extremely low Dispersion (XLD = extremely low dispersion) and excellent processing properties. The datasheet for N-FK58 XLD now also includes the temperature coefficients of refraction. This new data makes it possible to exactly determine the temperature dependence of the refractive index, allowing for minimal effects of temperature changes in the optical design and final performance of the application.
You will find the data here:
Interactive Abbe Diagram