A polyamic acid obtained from the reaction of(a) a non-phenylindane-containing polyfunctional amine; (b) a polyfunctional anhydride or ester thereof of the formula ##STR3## wherein Z is a tetravalent aryl radical; and R3 is hydrogen or C1 -C6 alkyl, with at least two R3 groups being alkyl; and (c) a monofunctional anhydride of the formula ##STR4## wherein R4 is allyl or methallyl; and R5 is hydrog