Dispersion and the thermo-optic coefficient

The TO coefficients of ChG glasses in particular, and optical materials In general, are much less well characterized than their 

In this case the change in refractive index with a change in temperature is positive rather than the negative change in the case of the wavelength shown in Fig. 7.20. As a reference, the change in refractive index dispersion for these materials measured by NASA is shown in Fig. 7.22 below. 

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