Process and apparatus are generally provided for forming a thin film photovoltaic device. In one particular embodiment, the process includes: depositing a photovoltaic absorber layer on a glass substrate; heating the glass substrate to an anneal temperature; and quenching the glass substrate to cool the glass substrate to a quenched temperature in less than 10 seconds. The quenched temperature can be about 85° C. to about 200° C. less than the anneal temperature. The quenching atmosphere can have a quenching pressure of about 1 torr or more and can include an inert gas.