A method of manufacturing an isolated polyetherimide composition, the method comprising combining an as-synthesized polyetherimide comprising units of the formula and 10 to 2,600 parts per million of anhydride equivalents, or 50 to 1,600 parts per million of anhydride equivalents, or 50 to 600 parts per million of anhydride equivalents, each based on the total weight of the as-synthesized polyetherimide, of an anhydride of the formula wherein in the foregoing formulas, R is a substituted or unsubstituted C 6-30 aromatic hydrocarbon group, a substituted or unsubstituted, straight or branched chain C 4-30 alkylene group, a substituted or unsubstituted C 3-8 cycloalkylene group, or a combination comprising at least one of the foregoing; Z is an aromatic C 6-30 monocyclic or polycyclic group optionally substituted with 1 to 6 C 1-8 alkyl groups, 1 to 8 halogen atoms, or a combination comprising at least one of the foregoing, and G is a hydrogen atom, a halogen atom, a nitro group, C 1-12 alkyl, C 2-12 alkenyl, C 2-12 alkynyl, C 1-12 haloalkyl. C 1-12 alkoxy, C 1-12 haloalkoxy, C 3-12 cycloalkyl. C 5-12 cycloalkenyl, C 6-18 aryl, C 7-31 arylalkylene, C 7-31 alkylarylene, C 4-12 heterocycloalkyl, C 3-18 heteroaryl, C 1-12 alkyl sulfonyl, C 6-12 arylsulfonyl, tosyl, or a group of the formulas wherein T is -O-Z-O-. a single bond, -O-, -S-, -C -, -SO 2 -, -SO-, -P(R c)(=O)-wherein R c is C 1-8 alkyl or C 6-12 aryl, NR d wherein R d is a hydrogen atom, C 1-8 alkyl, or C 6-12 aryl, or T is a C 1-18 organic bridging group, and X is chloro, bromo, iodo, or nitro, or a combination comprising at least one of the foregoing, to provide a mixture; and isolating a polyetherimide composition from the mixture, wherein isolating comprises melt extruding the mixture at 150 to 420°C, preferably at 180 to 400°C, more preferably at 180 to 370°C to provide the isolated polyetherimide composition having a change in complex viscosity measured over 30 minutes at 390°C, at a shear rate of 6.28 rad/seconds, strain= 5%, and under nitrogen, from +15 to -20%, preferably from +10 to - 20%,more preferably from 0 to -20%; and 0 to 3,000 parts per million, preferably 0 to 1,000 parts per million, more preferably 0 to 300 parts per million, each based on a total weight of the isolated polyetherimide composition and as determined by high pressure liquid chromatography, of a dianhydride of the formula R is a substituted or unsubstituted C 6-30 aromatic hydrocarbon group, a substituted or unsubstituted, straight or branched chain C 4-30 alkylene group, a substituted or unsubstituted C 3-8 cycloalkylene group, or a combination comprising at least one of the foregoing; Z is an aromatic C 6-30 monocyclic or polycyclic group optionally substituted with 1 to 6 C 1-8 alkyl groups, 1 to 8 halogen atoms, or a combination comprising at least one of the foregoing, and G is a hydrogen atom, a halogen atom, a nitro group, C 1-12 alkyl, C 2-12 alkenyl, C 2-12 alkynyl, C 1-12 haloalkyl. C 1-12 alkoxy, C 1-12 haloalkoxy, C 3-12 cycloalkyl. C 5-12 cycloalkenyl, C 6-18 aryl, C 7-31 arylalkylene, C 7-31 alkylarylene, C 4-12 heterocycloalkyl, C 3-18 heteroaryl, C 1-12 alkyl sulfonyl, C 6-12 arylsulfonyl, tosyl, or a group of the formulas wherein T is -O-Z-O-. a single bond, -O-, -S-, -C -, -SO 2 -, -SO-, -P(R c)(=O)-wherein R c is C 1-8 alkyl or C 6-12 aryl, NR d wherein R d is a hydrogen atom, C 1-8 alkyl, or C 6-12 aryl, or T is a C 1-18 organic bridging group, and X is chloro, bromo, iodo, or nitro, or a combination comprising at least one of the foregoing, T is -O-Z-O-. a single bond, -O-, -S-, -C -, -SO 2 -, -SO-, -P(R c)(=O)-wherein R c is C 1-8 alkyl or C 6-12 aryl, NR d wherein R d is a hydrogen atom, C 1-8 alkyl, or C 6-12 aryl, or T is a C 1-18 organic bridging group, and X is chloro, bromo, iodo, or nitro, or a combination comprising at least one of the foregoing, isolating a polyetherimide composition from the mixture, wherein isolating comprises melt extruding the mixture at 150 to 420°C, preferably at 180 to 400°C, more preferably at 180 to 370°C to provide the isolated polyetherimide composition having a change in complex viscosity measured over 30 minutes at 390°C, at a shear rate of 6.28 rad/seconds, strain= 5%, and under nitrogen, from +15 to -20%, preferably from +10 to - 20%,more preferably from 0 to -20%; and 0 to 3,000 parts per million, preferably 0 to 1,000 parts per million, more preferably 0 to 300 parts per million, each based on a total weight of the isolated polyetherimide composition and as determined by high pressure liquid chromatography, of a dianhydride of the formula