The present invention relates to curable compositions comprising at least one compound of the formula (1): wherein R is C1-C10 alkyl, and R1-R10 each are independently selected from the group consisting of hydrogen and C1-C10 alkyl, with the proviso that at least one of R1-R10 is alkyl, and wherein the substitution patterns formed by the residues R1-R5 and R6-R10 on each of the aromatic rings are different from each other, cured compositions obtained from such curable compositions, mixtures of compounds of the formula (I), the use of such compounds and mixtures of such compounds as a UV stabilizer in curable compositions, and a process for the manufacture of curable compositions comprising a UV stabilizer of the formula (1).