Fig. 5

Raman Hit quality indices (HQI) were measured on a subset of polymers for all treatments against a commercial library (ST Japan). Red lines (Reference) indicate which HQI level was reached using a spectrum of the untreated material of the respective polymer. Boxes show median HQI and .25 / .75 percentiles of a set of replicate spectra, n≥ 3. The grey box at the bottom provides the assigned qualitative categories for comparison. Note that categories were assigned in a manual spectral evaluation process and deliberately not based on the HQI values. Apparent discrepancies are discussed in the text. Both, manual categorisation and achieved HQI values, are resulting in the same predicate regarding polymer recognisability: the tested treatments do not alter spectra in a way that a successful polymer identification would be hindered