Surface Properties of Float Glass after Various Types of Heat Treatment

The surface properties of float glass tempered by air and by contact method have been studied. Air tempering was performed by traditional method, contact one was realized by a new method when a glass sample was fixed between the heat conductive plates and then heated to the temperature of tempering. Further, the glass cooling was carried out by water spraying. The changes in thickness, density, and contact angle were examined before and after tempering. It has been found that after tempering the thickness of samples increases, and the density and the hydrophilicity decreases. After further heat treatment at the temperature of tempering followed by slow cooling it has been found that due to stress relaxation the density, thickness and contact angle decrease.