DETERMINATION OF THE LOCAL TEMPERATURE AT A SAMPLE DURING RAMAN EXPERIMENTS USING STOKES AND ANTI-STOKES RAMAN BANDS

Sample heating due to high incident laser power in Raman experiments on (industrial) polymers and catalysts can easily lead to unwanted changes in morphology or desorption of surface species. Therefore temperature of the sample at the laser spot was studied by determining Stokes and anti-Stokes Raman intensities. Temperature can normally be determined within an accuracy of about 5 K, although for samples having nothing but Raman bands above 1000 cm-1, the anti-Stokes lines are very weak and accuracy of temperature determination decreased drastically. For most of the samples studied in the macro-Raman setup, powers up to 250 mW could be used without measurable heating. In the micro-Raman setup heating started earlier due to higher focusing.