When a polished piece of metal (or steel in particular) is heated to incandescence, how do its reflective properties change?
Given a mirror-like surface, would the object temporarily cease to act like a mirror at a certain temperature? Would the specular reflection of light turn into diffuse reflection; in other words, would the surface temporarily become matte/dull?
I am not asking about permanent changes to the object such as melting, but rather can there be a temporary change in the reflectivity only while the the object is hot, that disappears when the object is cooled down?
Background of the question: I have a laser scanner that usually has trouble scanning shiny surfaces with high specular/ low diffuse reflectivity; and it seems to work a lot better for hot steel pieces than for cold ones. Glowing steel also looks less shiny to me than cold steel, but of course that is hard to tell with all the glowing