A method of processing a glass material includes guiding and/or focusing light from a light source to glass material in a hot stage of a processing system, where the light source provides light at a wavelength λ that interacts with crystals that may be formed in the glass material. The method includes collecting and/or guiding light directed from the glass material in the hot stage to a wavelength separator, and separating the light directed from the glass material to provide a spectrum δ having wavelengths that are within about twenty nanometers of the wavelength λ. The method includes observing with a detector light of the spectrum δ to identify nano-scale shifts in the wavelength λ caused by interaction with crystals, if present, within the glass material in the hot stage of the processing system.