This proposal is part of our research efforts aimed at the understanding of the static and dynamic properties of cyclic polymers and their comparison to linear chains. Previous QENS experiments suggest similarity between the local dynamics of cyclic and linear poly(dimethylsiloxane)s (PDMSs), at relatively high molar mass values (ca. 10000). However, considerable differences have been seen by us for very small rings/linear chains. These appear to be consistent with other experimental observations but a systematic study is needed to confirm our results. Molar mass effects on local dynamics of rings have not been reported in the literature on this or other systems.