The present invention is directed to a RIM process and an isocyanate reactive composition for use therein. The isocyanate composition includes an amine terminated chain extender and an aromatic amine terminated polyether of the formula: ##STR1## wherein R is an n-valent group obtained by the removal of hydroxyl groups from an n-hydroxy group containing polyhydroxyl compound having a molecular weight of from about 300 to about 12,000,R.sub.1 represents hydrogen or an inert substituent,R.sub.2 represents hydrogen, an amine group, or an inert substituent, andn represents an integer from 2 to 4.