Glass-fiber membranes (GF membranes) grafted with poly(N-isopropylacrylamide containing triphenylmethane leucocyanide) [poly(NIPAAm-LeCN)] were prepared. Ultraviolet irradiation of the GF membranes with poly(NIPAAm-LeCN) induced a change in the phase-transition temperature of the poly(NIPAAm) segments. The changes in both the phase-transition temperature of the poly(NIPAAm) segments and the permeation rate of solutes are discussed in relation to the dissociation of LeCN molecules.