Environmental condition cumulative tracking integration sensor using shape memory polymer

摘要

The present invention utilizes the unique shape recovery properties of shape memory materials, especially shape memory polymers, to provide an inexpensive and easily identified method of determining when a product has been exposed to environmental conditions that would make it likely that the product has expired or is unfit for use. By allowing the shape memory material to alter its shape from a deformed shape to a memory shape in response to exposure to environmental conditions while attached to a visual indication device a viewer can easily determine if a product has expired.