The paper presents the electron spin resonance (ESR) measurements of nitroxide radical-containing PMNT-PEG-PMNT triblock copolymer in different solvents: water, dimethyl formamide (DMF) and chloroform. Temperature dependence of electron spin resonance spectra were measured for each probe and several spectroscopic parameters describing physical properties, such as g-spectroscopic splitting factor value, resonance field (H_r), peak-to-peak line width (ΔH_pp) and correlation time (τ) were calculated and discussed. For the determination of the parameters characterizing the dynamics of TEMPO radicals in complex spectra the computer resolution enhancement method (CREM) and EasySpin software for ESR spectra simulations were used.