Disclosed is a composition which comprises a polymer containing at least some monomer repeat units with photosensitivity-imparting substituents which enable crosslinking or chain extension of the polymer upon exposure to actinic radiation, said polymer being of the formula wherein x is an integer of 0 or 1, A is one of several specified groups, such as B is one of several specified groups, such as or mixtures thereof, and n is an integer representing the number of repeating monomer units, wherein said photosensitivity-imparting substitutents are allyl ether groups, epoxy groups, or mixtures thereof. Also disclosed is a process for preparing a thermal ink jet printhead containing the aforementioned polymers and processes for preparing the aforementioned polymers.