Industrial flame treatment is a common technique for oxidizing polymer films to improve adhesion and wettability. These processes are strongly influenced by flame properties such as temperature and the concentration of key combustion radicals (e.g., OH). In this work, we perform in-situ laser absorption measurements of line-of-sight averaged temperature, H2O and OH for an industrial premixed ribbon burner interacting with a chilled-roller polymer-treatment system. Measurements in the unobstructed flame exhibit profiles typical of premixed flames. The addition of a chilled roller above the flame significantly alters the temperature of the flame throughout its vertical profile and shifts the location of the maximum OH concentration above the burner. Measurements at the surface of the polymer, together with post analysis of the surface oxidation, directly verify previous numerical modeling results and surface characterization studies that suggested that the hydroxyl radical in the flame (OH) is critical to surface oxidation. This study may enable future active control of premixed burner systems to maintain desired wettability and adhesion properties of polymer films. © 2018 The Combustion Institute. Published by Elsevier Inc. All rights reserved.