INScore is an environment for augmented interactive music score design, oriented towards unconventional uses of music notation, without excluding conventional approaches. In this environment, although all the objects of a score have a temporal dimension, the time remains fixed i.e., the date (or duration) of an object does not change, except when a message is received (sent from an external application or resulting from events handling). Thus, INScore does not include a time manager in the classic sense of the term. This choice was based on the fact that the system was originally designed to be used with sound production software (e.g., Max/MSP, Pure Data), that have more strict real-time constraints than INScore's graphical environment. However, the need to introduce dynamic time has gradually emerged, leading to an original model, both continuous and event based. The paper presents this model and its properties in the frame on INScore.