A method of monitoring a surface temperature of a hot gas path component includes directing an excitation beam having an excitation wavelength at a layer of a sensor material composition deposited on a hot gas path component to induce a fluorescent radiation. The method includes measuring fluorescent radiation emitted by the sensor material composition. The fluorescent radiation includes at least a first intensity at a first wavelength and a second intensity at a second wavelength. The surface temperature of the hot gas path component is determined based on a ratio of the first intensity at the first wavelength and the second intensity at the second wavelength of the fluorescent radiation emitted by the sensor material composition.