Abstract The present work deals with the temperature measurements of a thin spherical liquid film surface during non-isothermal absorption with chemical reaction. The absorption of CO 2 into aqueous NaOH solutions has been used to test the proposed technique. The measurement is based on the use of an infrared pyrometer through a ZnSe window. The experimental results are compared to calculated values obtained from a previously described non-isothermal model. The measured and computed values of the flux of absorbed gas and the temperature profiles are very close without performing any parameter adjustment. The highest measured temperature increase is about 5 K, and despite this low thermal effect, the system has proved to be highly sensitive.