Side group rotations in amorphous polymers

Recently, conventional methods of analyzing the QENS data for side group rotations in polymers using a single Lorentzian line have been brought into question. Due to the amorphous structure of polymeric systems and therefore the inequality of side groups in different environments, a distribution of jumping rates or, alternatively, correlation times need to be considered. New methods of analysis have been developed. Here we consider two different approaches which have been used: the convolution method where a model function is constructed and, after convolution with the instrumental resolution, fitted to the experimental data and the deconvolution method based on the Fourier transform of the QENS spectra to obtain the intermediate scattering function. The two approaches are discussed and compared.