Luminescent thermal history sensing potential in Pr³⁺-activated YAG matrix

In this study, it was demonstrated that Pr³⁺-doped YAG powder can record thermal history in the temperature range of template provided by 1100–1600°C. Upon heating, the material undergoes irreversible structural phase transformations (YAM → YAP → single-phase YAG) induced by 2 h of thermal annealing, leading to permanent changes in both the emission intensity and the excited-state lifetime of Pr³⁺ ion. Temperature can be determined using two approaches: by analyzing the intensity ratio of the ³P₀→³H₄ and ¹D₂→³H₄ emission bands, which increases linearly over 1300–1600°C with a sensitivity of 0.001°C⁻¹, and by measuring the luminescence decay time of the ¹D₂→³H₄ transition, which decreases linearly over 1100–1600°C with a sensitivity of 0.38 µs·°C⁻¹. The combination of both methods enables durable and quantitative tracking of the material’s thermal history, confirming the suitability of YAG:Pr³⁺ powders for high-temperature diagnostics, thermal mapping, and monitoring of industrial processes.