Abstract: There are disclosed according to the invention copolymers having repeating structural units a) of the formula and b) of the formula (II) wherein m and p are each independently of the other whole numbers>0, n=1, o=1 or 0, Y is a bond or a group of the formula —CR2— or —CO—O—CR2—CR2—CR2—, each of the radicals R independently of the others is a H atom, an alkyl group, a group of the formula —CR′2—OR′, —OR′, —COOR′, —SiRcRdRe, or —NRd—Rc, an organic acid radical, its anhydride or its corresponding readily hydrolysable ester of the formula —O—CO—Rc or its corresponding readily hydrolysable amide of the formula —NRd—CO—Rc, a phenyl group optionally substituted by one or two —CR′═CR′2 groups, or a group of the formula —CReRfCHRg—SiX3, a group of the formula —SiOSiO(SiO)mH, an