Final answer:
After applying thioglycolate in a soft-curl perm, the correct step is not leaving it in for a longer period but rather rinsing the hair with warm water to prevent damage and achieve the desired result.
Step-by-step explanation:
When giving a soft-curl perm and after applying the thioglycolate (thio) until all hair on rods is thoroughly saturated, it is incorrect to leave the thio in for an extended period for better results. The correct step to take would be to rinse the hair with warm water.
The application of the thioglycolate solution reduces and ruptures some of the disulfide bonds in the hair's keratin structure. After the hair has been sufficiently processed with the reducing agent, an oxidizing agent, typically hydrogen peroxide, is used to neutralize the thio and reform the disulfide bonds in their new positions to create a permanent wave.