Quote... Taken from Glas Weld...
Glass is a super cooled liquid and can, even at ambient temperatures, flow. Glass in the windows of an old house, for example, is seen to be thicker at the bottom than at the top. The equipment developed by Glas Weld - Chicago Glass creates the conditions to cause the glass to flow back into the scratch caused by the damage.
Haha... What a load of bull crap!!
Glass cannot 'flow' at ambient temperatures, it will take temperatures of 400deg C plus depending on what type of glass
Glass in 'old houses' used to be hand rolled or 'drawn' therefore a uniform thickness could never be obtained. It won't have dropped due to gravity once it has been produced. It is now produced by 'floating' on mercury hence the name 'float' glass
I don't see or suppose that anyone could prove that the glass 'flows back into the scratch' during their process. They are removing the glass surrounding the scratch.
I have been working with glass for 16 years in many aspects commercially & domestically and have removed many hazes and scratches... It can be done... It can take a very long time... And time costs money!
Glas Weld do a very good job, my uncle used to be a tech for them