| abstract |
The invention relates to a photochromic coating compound, the essential components of which are as follows: a) a silicon-containing precondensate, derived from at least one hydrolysable silane A with at least one hydrolysis-stable rest R having a functional group X which is able to enter into a thermally and/or photochemically induced polyaddition, polymerisation or polycondensation reaction, and possibly from one or more additional hydrolysable compounds of elements of the group Si, Al, Ti, Zr, Ta, Nb, Sn, Zn, W and Ge; b) at least one photochromic dye; and c) at least one stabiliser. When said coating compound is applied onto substrates such as transparent plastic and glass and hardened it yields a coating characterized especially by high photostability and good scratch-resistance. |