Microstructured high molecular weight-low viscosity polyester polymers

In the solution polymerization process for the production of linear aromatic polyesters by reacting an organic diacid halide with a hydroxyl-containing component in the presence of a base catalyst, the improvement which comprises adding a hydroxyl-containing component comprising a combination of a bisphenol and 5 to about 95 mol percent of a glycol, to the diacid halide, wherein one member of the combination is added to and reacted with the diacid halide and thereafter a different member of the combination is added and reacted with the diacid halide, and the reaction is conducted at a temperature in the range of 0.degree. C. to 40.degree. C. to produce a polyester having an intrinsic viscosity of at least 0.6 dl/g in sym-tetrachloroethane at 30.degree. C and an alternation index of about 1.1 to 1.6;

• wherein the diacid halide is terephthaloyl chloride, isophthaloyl chloride or a mixture thereof, the glycol has 2-20 carbon atoms, and the bisphenol has the formula ##STR6## in which Ar is aromatic, each T is independently selected from the group consisting of halogen, G and OG, each G is independently selected from the group consisting of alkyl, aryl, haloaryl, haloalkylaryl, alkylaryl, cycloalkyl, halocycloalkyl, and haloalkyl, E is a bivalent alkylene, haloalkylene, cycloalkylene, halocycloalkylene, arylene, haloarylene, --O--, --S--, --SO--, --SO.sub.2 --, --SO.sub.3 --, --CO--, ##STR7## or GN<, m is 0 to the number of replaceable hydrogen atoms on E, each b is 0 to the number of replaceable hydrogen atoms on Ar, and d is 0 or 1.