Careful analysis of Fig. 2B reveals very little photodegradation of MC form since there is very little loss of the signal monitored at 560nm during the transformation from SP to MC (see signalsbetween semi-filled and open circles associated with dashedline in Fig. 2B).
The average difference in absorbance measured from transformation of SP to MC in five cycles is 0.237±0.007 a.u.
with virtually no loss in the signal between the 1st and the 5th cycle.