The novel time-temperature indicator label comprises an ammonia sensitive indicator layer film pressed onto a second film, comprising an ammonia-generating, adhesive layer. When separated the blue-coloured indicator film reverts back to its original (ammonia free) yellow form at a controllable, temperature dependant rate. The labels are easily made and stored.
Mills, A., Graham, A., Hawthorne, D., & Lawrie, K. (2016). Novel time-temperature and 'consume-within' indicator based on gas-diffusion. Chemical Communications, 13987-13990. https://doi.org/10.1039/C6CC07906G