Hot Stage Microscopy
The hot stage microscope (by Mettler Toledo, on an Olympus microscope) is a polarizing microscope with a stage compartment that is temperature controlled by a computer. A particle, fiber, or material of interest is mounted on a microscope slide, covered with a coverglass and placed into the chamber of the hot stage (light grey). To the right of the microscope is a controller used to control the temperature profile either manually or by means of an automated program to a temperature of 0.1° C up to ~350° C. By varying the temperature, the melting point of a substance can be determined. The hot stage can also be used to study polymorphic transformations, phase changes, sublimation, purity, recrystallization, waters of hydration, decomposition, or other thermal processes. One specific hot stage technique, GRIM, involves the precise measurement of glass refractive index and utilizes its own hot stage system, tracking temperature over a more narrow range to 0.01° C. When appropriate, these transformations can be recorded on video.