Increasing HCI work on affective interfaces aimed to capture and communicate users’ emotions in order to support self-understanding. While most such interfaces employ traditional screen-based displays, more novel approaches have started to investigate smart materials and actuators based prototypes. In this paper, we describe our exploration of smart materials and actuators leveraging their temporal qualities as well as common metaphors for real-time representation of changes in arousal through visual and haptic modalities. This exploration provided rationale for the design and implementation of six novel wrist-worn prototypes evaluated with 12 users who wore them over 2 days. Our findings describe how people use them in daily life, and how their material-driven qualities such as responsiveness, duration, rhythm, inertia, aliveness and range shape people’s emotion identification, attribution, and regulation. Our findings led to four design implications including support for affective chronometry for both raise and decay time of emotional response, design for slowness, and for expressiveness.