Disclosed herein is a compound of the formula (I), wherein one or two radicals of the radicals R1 are independently of one another C1-C20alkyloxy or C3-C12cycloalkyloxy and the remaining radicals R1 are independently of one another hydrogen, C1-C20alkyl or C3-C12cycloalkyl; the radicals R0 and R2 are independently of one another hydrogen, C1-C20alkyl, C3-C12cycloalkyl or a group of the formula (II-a) with R3 being hydrogen, C1-C20alkyl, C3-C12cycloalkyl, C1-C20alkyloxy or C3-C12cycloalkyloxy; Y is C2-C12alkylene; m is 0 or 1; n is 1, 2 or 3; when n is 1, X is hydrogen, C1-C20alkyl, C3-C12cycloalkyl or a group of the formula (II-a); when n is 2, X is C2-C12alkylene; when n is 3, X is a group N(Z—)3 with Z being C2-C12alkyl.