A process for the manufacture of alkoxylated derivatives of hydrogenated or (per)halogenated polymers comprising at least one -OH group [polymer (P ALK-OH )], said process comprising the steps of: (a) contacting at least one pre-catalyst [pre-catalyst C] complying with the following formula E(Q) t wherein E is an element selected from IV-group metals, post-transition metals and silicon, Q is chlorine, bromine, iodine or an optionally fluorinated alkoxy or aryloxy group, and t is an integer corresponding to the valence of E; with (a-i) at least one hydrogenated or (per)halogenated polymer comprising at least one -OH group [polymer (P OH )], thus providing a mixture [mixture (M a-1 )] comprising said polymer P OH and a product [product (C-P OH )] obtained by the reaction between said pre-catalyst C and said polymer (P OH ), or (a-ii) at least one source of iodine [compound I], thus providing a mixture [mixture (M a-2 )] comprising said pre-catalyst C and said compound (I); (b) contacting said mixture (M a-1 ) with at least one source of iodine [compound I] or contacting said mixture (M a-2 ) with at least one polymer (P OH ), thus obtaining mixture (M b ) comprising said polymer (P OH ), said product (C-P OH ) and said compound (I); (c) contacting said mixture (M b ) with at least one alkylene oxide, thus obtaining polymer (P ALK-OH ), optionally in admixture [mixture (M c )] with said polymer (P OH ), said product (C-P OH ) and/or said compound (I). (a) contacting at least one pre-catalyst [pre-catalyst C] complying with the following formula E(Q) t wherein E is an element selected from IV-group metals, post-transition metals and silicon, Q is chlorine, bromine, iodine or an optionally fluorinated alkoxy or aryloxy group, and t is an integer corresponding to the valence of E; with (a-i) at least one hydrogenated or (per)halogenated polymer comprising at least one -OH group [polymer (P OH )], thus providing a mixture [mixture (M a-1 )] comprising said polymer P OH and a product [product (C-P OH )] obtained by the reaction between said pre-catalyst C and said polymer (P OH ), or (a-ii) at least one source of iodine [compound I], thus providing a mixture [mixture (M a-2 )] comprising said pre-catalyst C and said compound (I); E is an element selected from IV-group metals, post-transition metals and silicon, Q is chlorine, bromine, iodine or an optionally fluorinated alkoxy or aryloxy group, and t is an integer corresponding to the valence of E; (a-i) at least one hydrogenated or (per)halogenated polymer comprising at least one -OH group [polymer (P OH )], thus providing a mixture [mixture (M a-1 )] comprising said polymer P OH and a product [product (C-P OH )] obtained by the reaction between said pre-catalyst C and said polymer (P OH ), or (a-ii) at least one source of iodine [compound I], thus providing a mixture [mixture (M a-2 )] comprising said pre-catalyst C and said compound (I); (b) contacting said mixture (M a-1 ) with at least one source of iodine [compound I] or contacting said mixture (M a-2 ) with at least one polymer (P OH ), thus obtaining mixture (M b ) comprising said polymer (P OH ), said product (C-P OH ) and said compound (I); (c) contacting said mixture (M b ) with at least one alkylene oxide, thus obtaining polymer (P ALK-OH ), optionally in admixture [mixture (M c )] with said polymer (P OH ), said product (C-P OH ) and/or said compound (I). <EOS>