In this study, the degradation behavior of oxide cathodes for cathode ray tubes (CRTs) is described using the stretched exponential model, which has been successfully used to describe the dynamics of complex systems characterized by heterogeneity. We derive a longevity equation from the two parameters: (i) characteristic life and (ii) heterogeneity parameter, which characterize the stretched exponential model. From the temperature dependences of the two parameters in the longevity equation, we reveal that the longevity follows the Arrhenius relation in oxide cathodes. The longevity equation and the Arrhenius relation enable us to predict the longevity in early life. The stretched exponential degradation is explained based on the heterogeneity of oxide cathodes. (c) 2005 Elsevier B.V. All rights reserved.