Employing enantiopure (R)-PO instead of racemic PO allows for deconvolution of the CH2 1 H-NMR resonances adjacent to the Sx links in the precipitated polymers for which analogous sets of signals can be observed (ESI Figure ). Comparing the Raman spectra of the precipitated polymers with small molecule standards for di-(R-S-S-R), tri-(R-S-S-S-R) and tetrasulfide (R-S-S-R) allowed us to draw some further conclusions about the Sx links (ESI Figure -15). At low sulfur loadings (run #5) disulfide links (sharp signal around ṽ = 507 cm -1 ) were mostly formed, while at higher sulfur loadings (run #3) tetrasulfide links (Figure )) were predominant. As Raman spectroscopy clearly revealed more R-S-Sy-R (y > 1) polysulfide versus R-S-S-R disulfide links at higher sulfur loading, we assigned the 1 H-NMR signal centred around 5.64 ppm to CH groups as part of repeat units containing R-S-S-R disulfide and the signal centred around 5.72 ppm to CH groups as part of repeat units containing R-S-Sy-R polysulfide links. By peak deconvolution in each case, the R-S-S-R to R-S-Sy-R ratios were found to change from 89:11 to 15:85 at low to high sulfur loadings. Next, we assessed the effects of different S8 to CS2 loading ratios (run #8 -#11) and found excellent sequence selectivities and similar molar masses in each case. However, polymer selectivity was somewhat decreased to 77% for lower CS2 loadings. Decreasing the catalyst loading at a fixed monomer ratio leads to larger obtained molar masses of Mw = 45 kDa (run #12), though the highest achievable molar mass appears to be limited. A decrease of the catalyst loading (run #13) does not lead to further increase of the molar mass beyond 45 kDa. Accordingly, GPC analysis of aliquots removed at regular time intervals revealed increasing molar masses with conversion, reaching a plateau in the high conversion regime (ESI Figure ). This could be due to the formation of cyclic polymers although the BnO end group could be identified, hence the copolymers are also likely linear chains. Nevertheless, molar masses between 10 -50 kDa seems to be typical for S8 ROCOP (and ROTERP), as reproducing a literature known S8/PS ROCOP at a comparable loading (run #14, compared to runs #2-4) gave copolymers with similar molar masses. Employing NaOBn or KOBn (run #15-16) instead of the LiOBn catalyst led to significantly slower indicating that Li acts as a true catalyst rather than a mere spectator counteraction to the chain end.