Phase transitions in non‐ionic surfactant–water systems as studied by Raman spectrometry. II—A new methodology

In order to compare the molecular Raman spectra between an optically isotropic phase and an anisotropic phase, a method is proposed having especially in view the study of transitions in lyotropic surfactant systems. Its application to the transition between the isotropic and hexagonal phases in the water‐α‐octyl‐ω‐hydroxypentakis (oxyethylene) system shows that there is no significant molecular structure change at transition. This result suggests that all the micelles in the L 1 phase in equilibrium with the hexagonal phase have a cylindrical shape.