Intermediate states in the melting process of low molecular weight poly(ethylene oxide).

The melting behavior of low molecular weight poly(ethylene oxide) (PEO) fractions has been studied via generalized two-dimensional infrared (2D-IR) correlation spectroscopy and a new stochastic-pulse-based temperature modulation differential scanning calorimetry (DSC) technique (TOPEM). 2D-IR correlation analysis of the melting of PEO shows that nu(s)(CH2) and gamma(a)(CH2) vary prior to nu(s)(COC). Moreover, the TOPEM experiments show that reversible melting and crystallization is occurring during the melting of PEO. These suggest that the melting of PEO is possibly a process passing over intermediate states. Based on our results, a model of the melting process of PEO lamellae is presented: the intermediate states containing the distorted helical conformation are formed first at the front of the lamellae during the melting process.