A polycarbonate composition comprising, relative to the total weight of the composition: a) 60 - 95 wt. % of a copolycarbonate comprising i) 42 - 90 mol% of an unit of formula wherein * indicates the position where formula is connected to the polymer chain, R 1, each independently, is hydrogen or C 1 -C 4 alkyl, R 2, each independently, is C 1 -C 4 alkyl, n is 0, 1, 2 or 3, and ii) 10 - 58 mol% of an unit of formula: wherein * indicates the position where formula is connected to the polymer chain, R 3, each independently, is H, linear or branched C 1 -C 10 alkyl, and R 4, each independently, is linear or branched C 1 -C 10 alkyl, wherein the mol% is calculated based on the total mole number of units of formula and formula, and b) 5 - 40 wt. % of a homopolycarbonate comprising an unit of formula as defined above, wherein the weight-average molecular weight of the homopolycarbonate is in the range of 24000- 28000g/mol, measured as indicated in the specification, wherein the content by weight of the unit of formula in the polycarbonate composition is 42-80 wt. %, relative to the total weight of the composition, and the total amount of the homopolycarbonate and the copolycarbonate in the composition is 96-100 wt. %, relative to the total weight of the composition. a) 60 - 95 wt. % of a copolycarbonate comprising i) 42 - 90 mol% of an unit of formula wherein * indicates the position where formula is connected to the polymer chain, R 1, each independently, is hydrogen or C 1 -C 4 alkyl, R 2, each independently, is C 1 -C 4 alkyl, n is 0, 1, 2 or 3, and ii) 10 - 58 mol% of an unit of formula: wherein * indicates the position where formula is connected to the polymer chain, R 3, each independently, is H, linear or branched C 1 -C 10 alkyl, and R 4, each independently, is linear or branched C 1 -C 10 alkyl, wherein the mol% is calculated based on the total mole number of units of formula and formula, and i) 42 - 90 mol% of an unit of formula wherein * indicates the position where formula is connected to the polymer chain, R 1, each independently, is hydrogen or C 1 -C 4 alkyl, R 2, each independently, is C 1 -C 4 alkyl, n is 0, 1, 2 or 3, and * indicates the position where formula is connected to the polymer chain, R 1, each independently, is hydrogen or C 1 -C 4 alkyl, R 2, each independently, is C 1 -C 4 alkyl, n is 0, 1, 2 or 3, and ii) 10 - 58 mol% of an unit of formula: wherein * indicates the position where formula is connected to the polymer chain, R 3, each independently, is H, linear or branched C 1 -C 10 alkyl, and R 4, each independently, is linear or branched C 1 -C 10 alkyl, wherein the mol% is calculated based on the total mole number of units of formula and formula, and * indicates the position where formula is connected to the polymer chain, R 3, each independently, is H, linear or branched C 1 -C 10 alkyl, and R 4, each independently, is linear or branched C 1 -C 10 alkyl, wherein the mol% is calculated based on the total mole number of units of formula and formula, and b) 5 - 40 wt. % of a homopolycarbonate comprising an unit of formula as defined above, wherein the weight-average molecular weight of the homopolycarbonate is in the range of 24000- 28000g/mol, measured as indicated in the specification, wherein the content by weight of the unit of formula in the polycarbonate composition is 42-80 wt. %, relative to the total weight of the composition, and the total amount of the homopolycarbonate and the copolycarbonate in the composition is 96-100 wt. %, relative to the total weight of the composition. wherein the content by weight of the unit of formula in the polycarbonate composition is 42-80 wt. %, relative to the total weight of the composition, and the total amount of the homopolycarbonate and the copolycarbonate in the composition is 96-100 wt. %, relative to the total weight of the composition.