A poly(ester-carbonate) copolymer, comprising carbonate units of the formula and ester units of the formula wherein: T is a C 2-20 alkylene, a C 6-20 cycloalkylene, or a C 6-20 arylene; and R 1 and J are each independently (a) a bisphenol A divalent group of the formula and (b) a C 16 or higher divalent group (b) of the formula wherein R c and R d are each independently a C 1-12 alkyl, C 2-12 alkenyl, C 3-8 cycloalkyl, or C 1-12 alkoxy, each R 6 is independently C 1-3 alkyl or phenyl, X a is a C 6-12 polycyclic aryl, C 3-18 mono- or polycycloalkylene, C 3-18 mono- or polycycloalkylidene, a -(Q 1) x -G-(Q 2) y - group wherein Q 1 and Q 2 are each independently a C 1-3 alkylene, G is a C 3-10 cycloalkylene, x is 0 or 1, and y is 1, and m and n are each independently 0 to 4; provided that the C 16 or higher divalent group (b) is present in an amount of 40 mol% to 50 mol% based on the total moles of the bisphenol A divalent groups and the C 16 or higher divalent groups; the ester units are present in an amount of 40 mol% to 60 mol% based on the sum of the moles of the carbonate units and the ester units; and wherein the poly(ester-carbonate) copolymer has a weight average molecular weight of 18,000 Daltons to 24,000 Daltons, as measured by gel permeation chromatography, using a crosslinked styrene-divinylbenzene column and calibrated to bisphenol A homopolycarbonate references; and a sample of the composition has a glass transition temperature of 210 °C to 235 °C as determined by differential scanning calorimetry as per ASTM D3418 with a 20 °C/min heating rate; and a melt viscosity of less than 1050 Pa·s at 644 sec -1 and 350°C, determined according to ISO11443. T is a C 2-20 alkylene, a C 6-20 cycloalkylene, or a C 6-20 arylene; and R 1 and J are each independently (a) a bisphenol A divalent group of the formula and (b) a C 16 or higher divalent group (b) of the formula wherein R c and R d are each independently a C 1-12 alkyl, C 2-12 alkenyl, C 3-8 cycloalkyl, or C 1-12 alkoxy, each R 6 is independently C 1-3 alkyl or phenyl, X a is a C 6-12 polycyclic aryl, C 3-18 mono- or polycycloalkylene, C 3-18 mono- or polycycloalkylidene, a -(Q 1) x -G-(Q 2) y - group wherein Q 1 and Q 2 are each independently a C 1-3 alkylene, G is a C 3-10 cycloalkylene, x is 0 or 1, and y is 1, and m and n are each independently 0 to 4; (a) a bisphenol A divalent group of the formula and (b) a C 16 or higher divalent group (b) of the formula wherein R c and R d are each independently a C 1-12 alkyl, C 2-12 alkenyl, C 3-8 cycloalkyl, or C 1-12 alkoxy, each R 6 is independently C 1-3 alkyl or phenyl, X a is a C 6-12 polycyclic aryl, C 3-18 mono- or polycycloalkylene, C 3-18 mono- or polycycloalkylidene, a -(Q 1) x -G-(Q 2) y - group wherein Q 1 and Q 2 are each independently a C 1-3 alkylene, G is a C 3-10 cycloalkylene, x is 0 or 1, and y is 1, and m and n are each independently 0 to 4; R c and R d are each independently a C 1-12 alkyl, C 2-12 alkenyl, C 3-8 cycloalkyl, or C 1-12 alkoxy, each R 6 is independently C 1-3 alkyl or phenyl, X a is a C 6-12 polycyclic aryl, C 3-18 mono- or polycycloalkylene, C 3-18 mono- or polycycloalkylidene, a -(Q 1) x -G-(Q 2) y - group wherein Q 1 and Q 2 are each independently a C 1-3 alkylene, G is a C 3-10 cycloalkylene, x is 0 or 1, and y is 1, and m and n are each independently 0 to 4; provided that the C 16 or higher divalent group (b) is present in an amount of 40 mol% to 50 mol% based on the total moles of the bisphenol A divalent groups and the C 16 or higher divalent groups; the ester units are present in an amount of 40 mol% to 60 mol% based on the sum of the moles of the carbonate units and the ester units; and the C 16 or higher divalent group (b) is present in an amount of 40 mol% to 50 mol% based on the total moles of the bisphenol A divalent groups and the C 16 or higher divalent groups; the ester units are present in an amount of 40 mol% to 60 mol% based on the sum of the moles of the carbonate units and the ester units; and the poly(ester-carbonate) copolymer has a weight average molecular weight of 18,000 Daltons to 24,000 Daltons, as measured by gel permeation chromatography, using a crosslinked styrene-divinylbenzene column and calibrated to bisphenol A homopolycarbonate references; and a sample of the composition has a glass transition temperature of 210 °C to 235 °C as determined by differential scanning calorimetry as per ASTM D3418 with a 20 °C/min heating rate; and a melt viscosity of less than 1050 Pa·s at 644 sec -1 and 350°C, determined according to ISO11443. a glass transition temperature of 210 °C to 235 °C as determined by differential scanning calorimetry as per ASTM D3418 with a 20 °C/min heating rate; and a melt viscosity of less than 1050 Pa·s at 644 sec -1 and 350°C, determined according to ISO11443.