Methods and systems for analysis of the polymerization material of high pressure polymerization processes are provided. In certain embodiments, the methods and systems subject the polymerization material to Raman spectroscopy analysis. The Raman spectroscopy provides analysis of reaction mixtures and/or product streams in high pressure polymerization processes. The Raman spectroscopy analysis may include both compositional and characterization analysis of the reaction mixtures and product streams. The spectroscopy results can be used to provide process control feedback to adjust operating parameters of the reactor operations and/or an associated polymerization product handling and finishing processes.