![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
Abstract
The transient response of nematic Phase V to a redirected magnetic field has been explored between 248 K and 272 K by EPR and a new EPR linewidth phenomenon accompanying this transient response has been discovered. The spin probles employed in this work were vanadyl acetylacetonate and 2-(14 carboxytetradecyl)-2-ethyl-4,4-dimethyl-3-oxazolidinyloxyl. The transient response for reorientation angles 25° or less leads to an EPR line broadening which relaxes exponentially to the equilibrium value. The relaxation time determined using the vanadyl spin probe at 260 K is 7.3 ± 0.5 sec., and the activation energy for the relaxation process is 14.7 ± 0.4 kcal/mole. Within experimental error there was no dependence of the measured relaxation parameters on the nature of the spin probe employed.