Low density polyethylene (LDPE) has been investigated with respect to the desorption/evaporation of hindered phenol antioxidants added to the polymer matrix. In this study, Fourier transform infrared and ultraviolet (FTIR and UV) spectroscopy without any extraction or refining steps in the analysis were used to measure the desorption constants. The UV spectrophotometer was equipped with an integrating sphere. The desorption constants, alpha, of five phenols containing the same 3,5-di-tert-butyl-4-hydroxyphenyl structure, but differing by the length of the hydrocarbon tails, were obtained in the temperature range of 40-100 degrees C. The number of methylene groups in the tail varied between 0 and 17. The temperature-dependence of the phenols could be described by an Arrhenius type relationship. Very large differences in desorption rates were found due to differences in size of the antioxidants.