GLASS SUBSTRATE FOR INFORMATION RECORDING MEDIUM AND MAGNETIC DISK

摘要

TO PROVIDE A PROCESS TO IMPROVE ACID RESISTANCE OF A GLASS SUBSTRATE FOR AN INFORMATION RECORDING MEDIUM. A PROCESS FOR PRODUCING THE GLASS SUBSTRATE FOR AN INFORMATION RECORDING MEDIUM, INCLUDES PROCESSING A GLASS FORMED INTO A PLATE BY A FLOAT PROCESS, A DOWN-DRAW METHOD OR A PRESS METHOD, WHEREIN, IN COOLING THE GLASS AT THE LAST STEP THE GLASS HAS A TEMPERATURE OF AT LEAST ITS STRAIN POINT, THE TIME DURING WHICH THE GLASS TEMPERATURE IS AT LEAST ITS STRAIN POINT AND AT MOST A TEMPERATURE WHERE THE GLASS VISCOSITY IS 10¹º dPa.s IS AT LEAST 13 MINUTES.