Henri Dutilleux described his croissance progressive (progressive growth) technique as a process in which "thematic elements" undergo gradual development such that by the end of the work, they "reach their definitive form" (Potter, 1997, 60/64). But this directional quality is thrown into question by some works whose main element from the beginning also appears at the end, suggesting, as Dutilleux also stated, "a notion of time as circular" (Nichols, 1994, 89). In this paper, I consider the string quartet, Ainsi la nuit (1976), and Mystère de l'instant for cimbalom, percussion and strings (1989), to show a broader conceptualization of the progressive growth technique in two ways. First, tendencies toward pitch and harmonic development are shown within and between these two compositions, reflecting Dutilleux's interest in writings by Proust and Jankélévitch. Second, temporally proportional analyses of selected movements suggest a striking connection to the Boulezian conceptions of smooth and striated musical time, in a highly idiosyncratic way: goal-oriented formal locations are consistently signified by a disruption or negation of metered subdivision and coordination between parts. To more fully realize the implications of this Boulezian connection, I suggest a new way of conceptualizing Dutilleux's forms in relation to Deleuzian theories on Chronos versus Aiôn, the undivided extended present versus a durationless instant separating past and future. In conclusion, I argue that the progressive growth technique can be understood to operate beyond conventional pitch and rhythm relationships, carrying deeper connections on levels of musical time and form.