A film, comprising 70 to 99 weight percent, preferably 75 to 95 weight percent, of an amorphous, high heat copolycarbonate having a glass transition temperature of at least 170°C, preferably 170 to 230°C, more preferably 175 to 200°C determined by differential scanning calorimetry, and 1 to 30 weight percent, preferably 5 to 25 weight percent of a cyclic olefin copolymer each based on the total weight of polymers in the film; wherein the film has a dielectric breakdown strength of greater than 700 Volts/micrometer, preferably 700 to 1250 Volts/micrometer determined in accordance with ASTM D149-09 at 150°C, wherein the copolycarbonate comprises first carbonate units of formula wherein R a and R b are each independently C 1-12 alkyl, C 1-12 alkenyl, C 3-8 cycloalkyl, or C 1-12 alkoxy, p and q are each independently 0 to 4, and X a is a single bond, -O-, -S-, -S -, -S 2 -, -C -, a C 1-11 alkylidene of the formula - C(R c)(R d)- wherein R c and R d are each independently hydrogen or C 1-5 alkyl, or a group of the formula -C(=R e)- wherein R e is a divalent C 1-6 hydrocarbon group; and second carbonate units of formula wherein R a and R b are each independently C 1-12 alkenyl, C 3-8 cycloalkyl, or C 1-12 alkoxy, p and q are each independently integers of 0 to 4, and X b is a C 3-8 cycloalkylene, a fused C 6-18 cycloalkylene, a group of the formula -J 1 -G-J 2 - wherein J 1 and J 2 are the same or different C 1-6 alkylene group and G is a C 3-12 cycloalkylene, a C 3-12 cycloalkylidene, or a C 6-16 arylene, a C 12-25 alkylidene of formula -C(R c)(R d)- wherein R c and R d are each independently hydrogen, C 1-24 alkyl, C 4-12 cycloalkyl, C 6-12 aryl, C 7-12 arylalkylene, C 7-12 heteroarylalkylene, C 7-12 alkylarylene, C 1-12 heteroalkyl, C 3-12 heterocycloalkyl, or C 7-12 heteroaryl, a group of the formula -C(=R e)- wherein R e is a divalent C 7-31 hydrocarbon group, a C 3-18 cycloalkylidene, a fused C 7-18 cycloalkylidene, or a fused C 6-18 heterocycloalkylidene. R a and R b are each independently C 1-12 alkyl, C 1-12 alkenyl, C 3-8 cycloalkyl, or C 1-12 alkoxy, p and q are each independently 0 to 4, and X a is a single bond, -O-, -S-, -S -, -S 2 -, -C -, a C 1-11 alkylidene of the formula - C(R c)(R d)- wherein R c and R d are each independently hydrogen or C 1-5 alkyl, or a group of the formula -C(=R e)- wherein R e is a divalent C 1-6 hydrocarbon group; and second carbonate units of formula R a and R b are each independently C 1-12 alkenyl, C 3-8 cycloalkyl, or C 1-12 alkoxy, p and q are each independently integers of 0 to 4, and X b is a C 3-8 cycloalkylene, a fused C 6-18 cycloalkylene, a group of the formula -J 1 -G-J 2 - wherein J 1 and J 2 are the same or different C 1-6 alkylene group and G is a C 3-12 cycloalkylene, a C 3-12 cycloalkylidene, or a C 6-16 arylene, a C 12-25 alkylidene of formula -C(R c)(R d)- wherein R c and R d are each independently hydrogen, C 1-24 alkyl, C 4-12 cycloalkyl, C 6-12 aryl, C 7-12 arylalkylene, C 7-12 heteroarylalkylene, C 7-12 alkylarylene, C 1-12 heteroalkyl, C 3-12 heterocycloalkyl, or C 7-12 heteroaryl, a group of the formula -C(=R e)- wherein R e is a divalent C 7-31 hydrocarbon group, a C 3-18 cycloalkylidene, a fused C 7-18 cycloalkylidene, or a fused C 6-18 heterocycloalkylidene. a C 3-8 cycloalkylene, a fused C 6-18 cycloalkylene, a group of the formula -J 1 -G-J 2 - wherein J 1 and J 2 are the same or different C 1-6 alkylene group and G is a C 3-12 cycloalkylene, a C 3-12 cycloalkylidene, or a C 6-16 arylene, a C 12-25 alkylidene of formula -C(R c)(R d)- wherein R c and R d are each independently hydrogen, C 1-24 alkyl, C 4-12 cycloalkyl, C 6-12 aryl, C 7-12 arylalkylene, C 7-12 heteroarylalkylene, C 7-12 alkylarylene, C 1-12 heteroalkyl, C 3-12 heterocycloalkyl, or C 7-12 heteroaryl, a group of the formula -C(=R e)- wherein R e is a divalent C 7-31 hydrocarbon group, a C 3-18 cycloalkylidene, a fused C 7-18 cycloalkylidene, or a fused C 6-18 heterocycloalkylidene.