Accordingly, further photo-excitation studies were carried out with 625 nm LED irradiation at 10 K. The evolution of absolute-reflectivity vs. time exhibits a faster increase in the absolutereflectivity value in compared to the white-light irradiation and attaining a saturation value after 3 min with a power of 16 mW/cm². In contrast to the white light, the saturation value matches well with one obtained at 350 K, which indicates a complete photoconversion to the photo-induced metastable HS state and thus suggests a complete photo-induced SCO of 1 state at 10 K under 625 nm light irradiation. After irradiation over 30 min, a fast isothermal relaxation of the metastable HS state at 10 K was noticed where the residual photo-excited part of the sample was only around 20% after 3 min and only around 4% after 30 min. The thermal relaxation is complete at 60 K.