Raman depth-profiling microspectroscopy provides rich information on chemical/physical characterization in a non-destructive mode with micrometric resolution. However, refraction causes distortions to the data obtained thereby. A method to determine the diffusivity of an additive in low linear density polyethylene (LLDPE) with Raman depth profiling is proposed, combining the latest developments on data treatment of refraction distorted profiles. The method is compared with the results obtained analysing the cross section of the sample, with a maximum 32% relative error between both methods. The main benefits, characteristics of this method, a discussion of the experimental errors, as well as perspectives for future work are highlighted.