Abstract. We present the results from the spectral index variability analysis for a sample of 12 newly discovered blazars. The blazars are selected from the sample of 47 Active Galac- tic Nuclei suggested for the link between Gaia Celestial Reference Frame and International Celestial Reference Frame. Blazars flux and spectra are highly variable in the whole electro- magnetic spectrum. The amplitude of variability could depend on a number of parameters, including luminosity and spectral properties of the source. We tested optical spectral index for variability, to see if there is any correlation with the flux variability. For two sources 0049+003 and 1612+378 spectral index variability is detected. Both sources are flat spec- trum radio quasars, and have confirmed flux variability. For the other sources we did not find correlations between their flux and spectral index variability.