Degradation of soiling for
C1 and C2 coatings are very similar, both for their values and trend,
during all the time under UV illumination.
Even in this case just the outer parts of the coating absorb or enter in contact with external
agent so degradation of soiling is not proportional to TiO2 content.
Decoloration of rhodamine B in the untreated case is due exclusively
to UV irradiation and, in a very different way in comparison
with C1 and C2 cases, it is slow and its rate is constant during all
time of UV illumination.