T ypical in this category are the arcyloxymethyl (or methacryloxymethyl) derivatives of organic silanes or polysiloxanes, for example, compounds of the types wherein R is hydrogen or methyl and the Rs are mono valent organic radicals, typically alkyl groups containing 1 to 18 carbon atoms, cyclohexyl, phenyl, toluyl, benzyl, diphenyl, or the like.