As part of a wider study we are investigating the effects of polymer architecture between cyclic and linear polymers. From ATR-FTIR measurements we observe clear differences between cyclic and linear POE diffusing into PMMA. There are several mechanisms which explain the diffusion data which we can not resolve with the ATR-FTIR measurements. To differentiate between the possible mechanisms we have begun NR measurements using our existing real-time liquid reflectivity cell to study the diffusion of cyclic and linear POE (molecular weights of 500, 1000 and 2000 g/mol) into thin dPMMA layers (Mw = 188k g/mol) in real time as a function of temperature. Following on from RB910400, where due to beam loss and shutter problems we were only able to measure data for one molecular weight PEO as a function of temperature, we ask for more beam time to complete these studies.