1. UBE Industries, Ltd., 8-1 Goi-minamikaigan, Ichihara, Chiba 290-0045, Japan
2. Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 606-01, Japan
3. Lehrstuhl für Physikalische Chemie II, Universität Bayreth, D-95440 Bayreuth, Germany