The temperature rising elution fractionation (TREF) analysis of linear and low-density polyethylene (PE) samples was investigated using an evaporative light scattering detector. Being less sensitive to pressure and temperature variations than the differential refractive index (DRI) detector, the ELSD allows the simplification of the flow path and reduction of the column dimensions. First experiments were done by quenching and capturing the injected polymer solution into a low volume TREF column. The elution profiles during the heating step showed that for each type of PE, clear correlations are found between the peak elution temperature and the PE density. Apart from having a signal to noise about 10 times better than DRI detection, the main advantage of the ELSD detector is the absence of the solvent peak. Because the solvent peak is evaporated by the ELSD, the initial 30 min of analysis can be used for dynamic cooling (meaning that the cooling step is done under solvent flow). Using dynamic cooling, we further develop the method to solve the challenging co-crystallization problem, when a mixture of low density and high-density PE is analyzed by TREF. By selecting specific dynamic cooling programs, it is possible to acquire in 30 min a baseline separation of two compounds and accurate peak elution temperatures, similar with those provided by classical TREF with a low cooling rate, performed over 11 h.