GB/T 2392-2014 "Dyes—Determination of thermal stability" specifies the test method for determining the thermal stability of reactive dyes and soluble vat dyes, and it is applicable for evaluating the thermal stability of these two types of dyes. The principle involves sealing the sample in an ampoule and baking it in an electrically heated constant temperature oven at 70°C for a specified period. The sample is then subjected to dyeing or printing using a laboratory dyeing or printing machine, and the results are compared with those of a sample that has not been baked. The thermal stability is characterized by evaluating changes in color shade and strength reduction. Instrumental methods may also be used as auxiliary means for determination. This standard provides a standardized technical basis for quality control in dye production, optimization of storage conditions, and selection of dyes for application.