Luminescent thermal history sensing potential in Pr 3+ -activated YAG matrix

In this study, it was demonstrated that Pr 3+ -doped YAG powder can record thermal history in the temperature range of the 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 Pr 3+ ion. Temperature can be determined using two approaches: by analyzing the intensity ratio of the 3 P 0 → 3 H 4 and 1 D 2 → 3 H 4 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 1 D 2 → 3 H 4 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:Pr 3+ powders for high-temperature diagnostics, thermal mapping, and monitoring of industrial processes.