| Abstract: | The thermal helix–coil transition of four samples of poly(γ-benzyl-L -glutamate) in the dioxane–dichloroacetic acid (DCA) mixture was studied by optical rotatory dispersion method. The transition occurred at very high DCA content (97.5% by weight) in this system. The transition parameters have been evaluated by two methods based on the theories of Zimm and Bragg and of Nagai. The values of the helix initiation parameter and of the enthalpy of transition were found to be (4.4 ± 0.4) × 10?5 and 340 cal/mole, respectively. The range of validity and equivalence of the two methods is discussed. |
