second embodiment of the present invention provides a further method of producing an isosorbide-containing polycarbonate. The method comprises the steps of:
(i) preparing a polycarbonate by reacting isosorbide with a diaryl carbonate in the presence of a polymerization catalyst under polymerization conditions, and
(ii) performing a polycarbonate treatment step selected from the group consisting of: (a) testing the polycarbonate prepared in step (i) for the presence of a sorbitol-derived color body associated with a 1H-NMR peak located at a chemical shift of about 2.55 ppm in a 1H-NMR spectrum, and if the sorbitol-derived color body is present, treating the polycarbonate prepared in step (i) to reduce the level of the sorbitol-derived color body, and (b) treating the polycarbonate prepared in step (i) to reduce the level of the sorbitol-derived color body, thereby producing an isosorbide-containing polycarbonate product.