Polyhydroxylated photoinitiators

A compound according to the following formula (I):

• wherein
• PI is a photoinitiator moiety;
• each L is independently selected from a direct bond or a linker comprising 1 to 20 carbon atoms;
• each X is independently selected from a direct bond, a —P(—O)(R′)— bond and a linker comprising 1 to 6 carbon atoms;
• R′ is aryl, alkyl or alkoxy;
• each Y is independently H, alkyl or —Z′—(OM′)m′;
• each Z and Z′ is independently a linker comprising 1 to 6 carbon atoms;
• each M and M′ is independently H or (meth)acryloyl;
• each m and m′ is independently 1, 2 or 3;
• each n is independently 0 or 1;
• each p is independently 1, 2 or 3;
• q is 1, 2 or 3r;
• with the proviso that the following conditions are met:
• the compound of formula (I) comprises a —P(═O)(R′)— bond or at least two —N(Y)—Z—(OM)m moieties where Y is other than H;
• when L is a direct bond, it is directly connected to a —C(═O)—X— moiety;
• the -L-[C(═O)—X]n— moieties and the —Z— moieties are devoid of ester bonds,