the glaze is heated to fusion range in the kiln, the volume of the
glaze increases as a result of the physical and chemical changes
taking place in the process.
the glass cools the glaze, which expanded while being heated, contracts.
same process of expansion and contraction occurs in the clay body
to a different degree due to the different chemical makeup of the
coefficient of expansion is a measure of how much the glaze has
changed in volume as a result of firing.
glaze or clay body will have a different coefficient of expansion
each reflecting the unique chemical composition of the glaze or