Analysis of Structural Changes in Permanent Waved Human Hair Using Raman Spectroscopy

The study used Raman spectroscopy to analyze structural changes in permanent waved white human hair, revealing that the β-sheet/random coil content increased and α-helix content decreased in the cortex region, indicating a shift from α-helix to random coil forms in hair proteins. Despite this, the SS band intensity in the cortex matrix remained unchanged. Transmission electron microscopy showed significant disturbance in the cortex's macrofibril structure, while the cuticle remained largely unaffected. These changes in the cortex proteins were concluded to cause the reduction in tensile strength of the hair post-treatment.