A curable composition comprising a) at least one polymer having at least one terminal group of the general formula -A n -R-SiXYZ, wherein A is a divalent or trivalent bonding group containing at least one heteroatom, R is selected from divalent hydrocarbon residues having 1 to 12 carbon atoms, X, Y, Z are, independently of one another, selected from the group consisting of a hydroxyl group and C 1 to C 8 alkyl, C 1 to C 8 alkoxy, C 1 to C 8 acyloxy groups and -CH 2 -N-R' wherein N is oxygen, nitrogen or sulfur, preferably oxygen, and R' is selected from C 1 to C 8 alkyl groups, wherein X, Y, Z are substituents directly bound with the Si atom or two of the substituents X, Y, Z form a ring together with the Si atom to which they are bound, and at least one of the substituents X, Y, Z is selected from the group consisting of a hydroxyl group, C 1 to C 8 alkoxy and C 1 to C 8 acyloxy groups, and n is 0 or 1; and b) at least one compound of the general formula wherein R 1 is same or different and is, independently from one another, selected from the group consisting of a hydrogen atom and hydrocarbon residues having 1 to 12 carbon atoms, R 2 is same or different and is, independently from one another, selected from hydrocarbon residues having 1 to 12 carbon atoms, Ar is selected from aryl groups, and n is an integer selected from 3 to 9, wherein the composition comprises the at least one compound of the general formula in an amount of 1 to 60 wt.% based on the total weight of the composition. a) at least one polymer having at least one terminal group of the general formula -A n -R-SiXYZ, wherein A is a divalent or trivalent bonding group containing at least one heteroatom, R is selected from divalent hydrocarbon residues having 1 to 12 carbon atoms, X, Y, Z are, independently of one another, selected from the group consisting of a hydroxyl group and C 1 to C 8 alkyl, C 1 to C 8 alkoxy, C 1 to C 8 acyloxy groups and -CH 2 -N-R' wherein N is oxygen, nitrogen or sulfur, preferably oxygen, and R' is selected from C 1 to C 8 alkyl groups, wherein X, Y, Z are substituents directly bound with the Si atom or two of the substituents X, Y, Z form a ring together with the Si atom to which they are bound, and at least one of the substituents X, Y, Z is selected from the group consisting of a hydroxyl group, C 1 to C 8 alkoxy and C 1 to C 8 acyloxy groups, and n is 0 or 1; and A is a divalent or trivalent bonding group containing at least one heteroatom, R is selected from divalent hydrocarbon residues having 1 to 12 carbon atoms, X, Y, Z are, independently of one another, selected from the group consisting of a hydroxyl group and C 1 to C 8 alkyl, C 1 to C 8 alkoxy, C 1 to C 8 acyloxy groups and -CH 2 -N-R' wherein N is oxygen, nitrogen or sulfur, preferably oxygen, and R' is selected from C 1 to C 8 alkyl groups, wherein X, Y, Z are substituents directly bound with the Si atom or two of the substituents X, Y, Z form a ring together with the Si atom to which they are bound, and at least one of the substituents X, Y, Z is selected from the group consisting of a hydroxyl group, C 1 to C 8 alkoxy and C 1 to C 8 acyloxy groups, and n is 0 or 1; and b) at least one compound of the general formula wherein R 1 is same or different and is, independently from one another, selected from the group consisting of a hydrogen atom and hydrocarbon residues having 1 to 12 carbon atoms, R 2 is same or different and is, independently from one another, selected from hydrocarbon residues having 1 to 12 carbon atoms, Ar is selected from aryl groups, and n is an integer selected from 3 to 9,