The present invention relates to a photo-polymerized, patterned or unpatterned liquid crystal polymer, especially a liquid crystal polymer film or a liquid crystal polymer network, comprising thio-ether units of formula (I) * covalent bond, which links the unit of formula (I) to the residue of the polymer wherein LC1 is selected from the group of liquid crystal residues, X1 is selected from the group of aliphatic organic residues, and n1 is an integer ≧0 and m1 is an integer ≧0; with the proviso that if n1 is 0, then m1 is >0, and if m1 is 0, then n1>0; which is prepared in an atmosphere containing oxygen, preferably with an amount of 0.1≦oxygen 50%, more preferably 1≦oxygen≦25%, most preferably in air; with the proviso that polymer dispersed liquid crystals are excluded. Further, this invention relates to a composition used for the preparation of that photo-polymerized liquid crystal polymer of the invention, to processes of the preparation of that liquid crystal polymer and to its use.