The objective of this study was to learn the effect of the amount of processing time on hair during the heating far-infrared ray silicon
perm. To do so, a perm was given to subjects, differentiating the processing time for each subject. The hair thickness and tensile strength
were compared and the proteolytic ability were observed using the methylene bule(MB) stain. Following conclusion was obtained from
the SEM observation, electron microscope observation, and comparison of ability to form and maintain wave. For both virgin hair and
dyed hair, longer processing time meant thinner hair and weaker tensile strength; however the O. D value of MB increased. From the
SEM and optical microscope observation, it was found that the longer processing time led to dry cuticle end, which breaks the end. The
ability to form and maintain wave improved with the longer processing time.