title: Hair color changes caused by dyeing and thermal treatments.
abstract: The aim of this study was to show the effect of heat exposure, dyeing, and shampooing on hair color as measured by diffuse reflectance spectrophotometry. Successive dyeing of virgin hair with six permanent commercial formulations showed that color saturation was obtained after the first dyeing cycle. An unexpectedly high difference in hair color saturation, measured as DE* values, was obtained for virgin hair samples that differed only in cleansing history. After six sequential washings of the dyed hair samples, no difference was observed in color durability, indicating that the adhesion strength is similar to long-lasting and tone-up dyeing formulations. Exposure to a hot plate at 172 degrees C showed a significant darkening of the virgin hair samples after 2 min. On the other hand, virgin hair samples exposed to the gentler heat of a hand dryer (approximately 60 degrees C) showed partial disappearance of the hair medulla after 60 min. However, values of total color difference were near the error limit.
authors.affiliation: Instituto de Química, Universidade Estadual de Campinas (UNICAMP), Caixa Postal 6154, 13084-971 Campinas, SP, Brazil.
authors.forename: Ana Carolina Santos
authors.initials: AC
authors.lastname: Nogueira
authors.forename: Carla
authors.initials: C
authors.lastname: Scanavez
authors.forename: Cristiane
authors.initials: C
authors.lastname: Carnelos
authors.forename: Alexandre
authors.initials: A
authors.lastname: Gaspari
authors.forename: Inés
authors.initials: I
authors.lastname: Joekes
mesh_terms: D006197:Hair / Q000187:drug effects* / Q000502:physiology; D006200:Hair Color / Q000187:drug effects*; D006202:Hair Dyes / Q000737:chemistry* / Q000494:pharmacology*; D006358:Hot Temperature; D006801:Humans; D008853:Microscopy; D013053:Spectrophotometry
chemical_list: D006202:Hair Dyes