Amorphous perfluorinated homopolymers and copolymers of perfluorodioxoles of formula (IA): wherein R′F is equal to RF or ORF wherein RF is a linear or branched perfluoroalkyl radical having 1–5 carbon atoms; X1 and X2, equal to or different from each other, are F, CF3; said polymers having a dioxole content ≧95% by moles, having the following property combination: Tg, measured according to the ASTM 3418 (DSC) method, from 180° C. to 195° C.; intrinsic viscosity, measured at the temperature of 30° C. in perfluoroheptane (Galden® D80) according to the ASTM D2857-87 method, from 13 cc/g to 100 cc/g.