Spectral dependence of Sgr A* fractional polarization, fitted with a power-law p(ν)∝ν^α. Both LP and CP measurements indicate a rapid depolarization with decreasing frequency at about 100 GHz (2017 April 3) in contrast to a weak dependence of fractional polarization at observing frequencies above 200 GHz (2017 April 6). The error bars represent the standard deviation in the samples and are dominated by the intrinsic source variability, while the formal uncertainties of the spectral index fits are very small (see Table 1).