Tempered glass is already stronger and more durable than regular glass due to the tempering process, which involves heating the glass to a high temperature and then rapidly cooling it. However, there is still a risk of spontaneous breakage due to the presence of nickel sulfide inclusions within the glass. These inclusions can expand over time and cause the glass to shatter. This is what is the so-called " butterfly effect". 
Heat soaking is a process that involves subjecting tempered glass to a prolonged period of heat in order to accelerate the expansion of any nickel sulfide inclusions that may be present. This allows any potentially problematic pieces of glass to break during the heat soaking process, rather than after the glass has been installed.
By heat soaking tempered glass, the risk of spontaneous breakage is significantly reduced, making it a safer and more reliable option for use in buildings and other applications where safety is a concern. Additionally, heat soaking can help to identify any defective pieces of glass before they are installed, saving time and money in the long run.
