It is shown that kinetics of polyethylene thermooxidative degradation is influenced by both spatial and temporary (energetic) disorder of structure. Thus, the theorem of subordination is carried out (i.e., the multiplicative behavior of exponents describing these kinds of disorder is observed). As heat aging is usually carried out at rather high temperatures, this circumstance leads in an increase of contribution of temporary (energetic) disorder. (C) 2004 Wiley Periodicals, Inc.