Figure 3. Total light transmission as a function of applied linearly increasing/decreasing voltage between 0 and -1.5 V and back to 0 V.

From

Electrochromism of Methylviologen (Paraquat)

N. Aristov, A. Habekost

World Journal of Chemical Education. 2015, 3(4), 82-86 doi:10.12691/wjce-3-4-1