. "0 to 4; B is a member selected from the group consisting essentially of hydrogen, alkyl having from 1 to 3 carbon atoms, halo, alkoxy having from 1 to 3 carbon atoms, hydroxyl, vitro, and amino; a is a number varying from 0 to 4; b is an integer varying between 6 and 10; --OR is an acid labile group; I is an inert acid ester blocking group, x is the mole fraction of the units having hydroxyl subst" . . .