Photochromism of spirooxazines in mesoporous organosilica films†
Abstract
In order to increase the colourability and improve the mechanical properties of sol–gel photochromic films, we present an original strategy in which spirooxazine (SO) molecules are dispersed in mesoporous organized films using the impregnation technique. Two types of SO photochromic molecules are trapped in sol–gel matrices. The first one allows optimization of the chemical and steric interactions between SO molecules and the sol–gel matrix. The second one leads to fast photochromism as previously observed in soft hydrophobic sol–gel matrices and mesostructured