A method of processing a glass material, comprising steps of: guiding and/or focusing light from a light source to glass material in a hot stage of a system for processing the glass material, wherein the glass material comprises glass that may form crystals therein and/or glass-ceramic having crystals formed therein, wherein the light source provides light at a wavelength λ that interacts with crystals that may be formed in the glass material, wherein the hot stage of the system at least partially surrounds the glass material, and wherein at least some of the glass material is at a temperature of at least two-hundred degrees Celsius; collecting and/or guiding light directed from the glass material in the hot stage of the system and directing the light directed from the glass material to a wavelength separator; separating the light directed from the glass material with the wavelength separator to provide a spectrum δ of the light directed from the glass material having wavelengths that are within about twenty nanometers of the wavelength λ of the light from the light source; observing light of the spectrum δ of the light with a detector to view nano-scale shifts in the wavelength λ of the light from the light source caused by interaction with crystals, if present, within the glass material; receiving crystallization information about the glass material in the hot stage of the system from the detector; and changing conditions in the hot stage as a function of the crystallization information. guiding and/or focusing light from a light source to glass material in a hot stage of a system for processing the glass material, wherein the glass material comprises glass that may form crystals therein and/or glass-ceramic having crystals formed therein, wherein the light source provides light at a wavelength λ that interacts with crystals that may be formed in the glass material, wherein the hot stage of the system at least partially surrounds the glass material, and wherein at least some of the glass material is at a temperature of at least two-hundred degrees Celsius; wherein the glass material comprises glass that may form crystals therein and/or glass-ceramic having crystals formed therein, wherein the light source provides light at a wavelength λ that interacts with crystals that may be formed in the glass material, wherein the hot stage of the system at least partially surrounds the glass material, and wherein at least some of the glass material is at a temperature of at least two-hundred degrees Celsius; collecting and/or guiding light directed from the glass material in the hot stage of the system and directing the light directed from the glass material to a wavelength separator; separating the light directed from the glass material with the wavelength separator to provide a spectrum δ of the light directed from the glass material having wavelengths that are within about twenty nanometers of the wavelength λ of the light from the light source; observing light of the spectrum δ of the light with a detector to view nano-scale shifts in the wavelength λ of the light from the light source caused by interaction with crystals, if present, within the glass material; receiving crystallization information about the glass material in the hot stage of the system from the detector; and changing conditions in the hot stage as a function of the crystallization information. <EOS>