Spoiled perishable products, such as food and drugs exposed to inappropriate temperature, cause million illnesses every year. Risks range from intoxication due to pathogen-contaminated edibles, to suboptimal potency of temperature-sensitive vaccines. High-performance and low-cost indicators are needed, based on conformable materials whose properties change continuously and irreversibly depending on the experienced time-temperature profile. However, these systems can be limited by unclear reading, especially for colour-blind people, and are often difficult to be encoded with a tailored response to detect excess temperature over varying temporal profiles. Here we report on optically-programmed, non-colorimetric indicators based on nano-textured non-wovens encoded by their cross-linking degree. This combination allows a desired time-temperature response to be achieved, to address different perishable products. The devices operate by visual contrast with ambient light, which is explained by backscattering calculations for the complex fibrous material. Optical nanomaterials with photo-encoded thermal properties might establish new design rules for intelligent labels.

变质的易腐产品，例如暴露在不适当温度下的食物和药品，每年会导致数百万种疾病。风险范围从因病原体污染的食物引起的中毒到对温度敏感的疫苗的次优效价。需要高性能和低成本的指示器，这些指示器基于适形的材料，其性能会根据所经历的时间-温度曲线连续且不可逆地变化。但是，这些系统可能受到阅读不清晰的限制，尤其是对于色盲人而言，并且通常难以通过量身定制的响应进行编码，以检测变化的时间范围内的温度过高。在这里，我们报告了基于纳米交织度编码的纳米织构非织造布的光学编程非比色指示剂。这种组合可以实现所需的时间-温度响应，以解决不同的易腐烂产品。这些设备通过与环境光的视觉对比来操作，这可以通过对复杂纤维材料进行反向散射计算来解释。具有光编码热性能的光学纳米材料可能会建立智能标签的新设计规则。