Numbers of proposals to incorporate delegation into secure service management have been seen the last years. How to assure that only the authorized users can fulfill specify services is one of the main problems for secure service management. Delegation is a mechanism that permits a user to assign a subset of his/her assigned authorizations to other users who currently do not possess the authorization. Users may delegate the authority of fulfilling a service to others, especially at certain time periods. In this paper, we introduce a formal temporal delegation model, by extending the notion of delegation model which use a logic-based language called delegation logic (DL). Furthermore, an implementation architecture is outlined.