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Yellowing and bleaching of grey hair caused by photo and thermal degradation

Paper ID Volume ID Publish Year Pages File Format Full-Text
30296 44468 2014 10 PDF Available
Title
Yellowing and bleaching of grey hair caused by photo and thermal degradation
Abstract

•We show that incidence of full-spectrum radiation on white hair can result in both yellowing or bleaching.•The VIS fraction of the spectrum directs the process towards bleaching.•Thermal degradation (at 81 °C) always leads to yellowing in white hair.•Dark-follow reactions occur after irradiation or thermal treatment.

Yellowing is an undesirable phenomenon that is common in people with white and grey hair. Because white hair has no melanin, the pigment responsible for hair colour, the effects of photodegradation are more visible in this type of hair. The origin of yellowing and its relation to photodegradation processes are not properly established, and many questions remain open in this field. In this work, the photodegradation of grey hair was investigated as a function of the wavelength of incident radiation, and its ultrastructure was determined, always comparing the results obtained for the white and black fibres present in grey hair with the results of white wool.The results presented herein indicate that the photobehaviour of grey hair irradiated with a mercury lamp or with solar radiation is dependent on the wavelength range of the incident radiation and on the initial shade of yellow in the sample. Two types of grey hair were used: (1) blended grey hair (more yellow) and (2) grey hair from a single-donor (less yellow). After exposure to a full-spectrum mercury lamp for 200 h, the blended white hair turned less yellow (the yellow–blue difference, Db* becomes negative, Db* = −6), whereas the white hair from the single-donor turned slightly yellower (Db* = 2). In contrast, VIS + IR irradiation resulted in bleaching in both types of hair, whereas a thermal treatment (at 81 °C) caused yellowing of both types of hair, resulting in a Db* = 3 for blended white hair and Db* = 9 for single-donor hair. The identity of the yellow chromophores was investigated by UV–Vis spectroscopy. The results obtained with this technique were contradictory, however, and it was not possible to obtain a simple correlation between the sample shade of yellow and the absorption spectra. In addition, the results are discussed in terms of the morphology differences between the pigmented and non-pigmented parts of grey hair, the yellowing and bleaching effects of grey hair, and the occurrence of dark-follow reactions.

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Keywords
Photo damage; Human hair; White hair; Hair colour; UV-light
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 138, 5 September 2014, Pages 172–181
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us