1. Institute of Macromolecular Compounds, Russian Academy of Sciences; Bolshoi pr. 31 (V.O.) St. Petersburg 199004 Russia
2. Saint-Petersburg National Research University of Information Technologies, Mechanics, and Optics; Kronverkskii pr., 49 St. Petersburg 197101 Russia
3. Department of Physics; St. Petersburg State University; Ul'yanovskaya str. 1 Petrodvorets St. Petersburg 198504 Russia
4. St.Petersburg State Polytechnic University; Polytechnicheskaya str. 29, St.Petersburg 195251 Russia