As part of a wider study we are studying 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 plan to use our existing real-time liquid reflectivity cell to study the diffusion of cyclic and linear POE (both of molecular weight of 900 g/mol) into thin dPMMA layers (Mw = 188k g/mol) in real time. We anticipate that given the repetition rate, wavelength and flux on INTER we will be able to measure the inter-diffusion between the polymers in real time by collecting reflectivity profiles with a few seconds data capture time over an extended Q range.