TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: Core component further comprises greater than or equal to 1 additives. Additive comprises long-chain alkyl compound.    TECHNOLOGY FOCUS - POLYMERS - Preferred Compositions: Fiber or film comprises greater than or equal to 2 co-spun or co-extruded components configured in core component-sheath component cross-sectional geometry in which core component comprises thermoplastic elastomer capable of forming physically-crosslinked network, sheath component comprises polyolefin capable of transitioning in response to thermal stimulus, and fiber can be deformed from original shape, retain temporary shape, and subsequently return to its original shape in response to thermal stimulus. Thermoplastic elastomer comprises styrenic block copolymer selected from poly(styrene-b-butadiene-b-styrene) (SBS), poly(styrene-b-isoprene-b-styrene) (SIS), poly(styrene-b-(ethylene-co-propylene)-b-styrene) (SEPS), and poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS). Sheath component comprises linear low density polyethylene (LLDPE). Core component comprises SEBS, and sheath comprises LLDPE. Sheath component and core component are present in fiber in (sheath/core) w/w ratio of 95/5, 90/10, 85/15, 80/20, 75/25, 70/30, 65/35, 60/40, 55/45, 50/50, 45/55, 40/60, 35/65, 30/70, 25/75, 20/80, 15/85, 10/90, or 5/95, preferably 40/60. Fiber or film comprises 3 co-spun or co-extruded components configured in inner core component-outer core component-sheath component cross-sectional geometry in which greater than or equal to 1 of core components comprise thermoplastic elastomer and sheath component comprises polyolefin. Inner core component/outer core component/sheath component comprise LLDPE/SEBS/LLDPE. Preferred Processes: Fiber or film returns to original shape within approximately 5 s, preferably approximately 2 s after being exposed to thermal stimulus. Preferred Parameters: Fiber or film exhibits repeatable shape recovery property and is capable of deforming to greater than or equal to 4 times an original length. Sheath component has melting point lower than the upper glass transition temperature of network-forming core component. Core component has upper glass transition temperature of 90-140 degrees C. Core component comprising greater than or equal to 1 additives has higher upper glass transition temperature than core component without additives.