Polyethylene and polymethylmethacrylate were irradiated with intense beam of high-energy electrons or with 'white' beam of synchrotron radiation with different doses. Results of changes in structure after irradiation ex situ and in situ during heating up to melting point for polyethylene are presented using synchrotron radiation X-Ray diffraction. Measurements were performed using SR from the VEPP-3 storage ring (C) 2016 The Authors. Published by Elsevier B.V.