Sample of patent prismatic rolled glass by Pilkington Brothers Ltd., St. Helens, England, 1892-1930. Glass is fluid at high temperatures and its fluidity decreases as the temperature is reduced. Glass does not have a specific melting or freezing point but gradually changes from the solid state to the liquid state as the temperature is increased. This property of variable viscosity is used when glass is formed into objects, whether of beauty or utility.The two manufacturing processes for producing flat glass in the UK are the float glass method and rolling. In rolling a continuous stream of molten glass is poured between water-cooled rollers.