Abstract: Polymers, hydrogels, and thermochromic agents, including products embodying them, methods of using them, and processes for making them. In certain embodiments, temperature therapy packs which utilize thermochromic agents integrated into solid, semi-solid, or liquid hydrogels. In preferred (but optional) embodiments, the thermochromic agents are integrated into the composition used as the temperature exchange material of the therapy pack. In certain other embodiments, methods of using the thermochromic integrated temperature exchange materials, or processes for manufacturing such thermochromic integrated temperature exchange materials and/or methods or processes for manufacturing or using thermal packs embodying such materials. In certain particularly preferred embodiments, novel polymer compositions and/or processes for making polymers, which improve product durability or longevity and/or which improve use cycles or usage times.