“Glass Hair”: Innovative measurement of shine and smoothness in hair care
“Glass hair” refers to a hair condition characterised by an exceptionally smooth and uniform surface, giving the fibre a near glass-like appearance. This visual effect results from a perfectly aligned and tightly sealed cuticle, which reduces surface roughness and promotes optimal specular reflection of light.
From a physico-chemical perspective, this state corresponds to a significant reduction in porosity and inter-fibre friction. It is typically achieved through a combination of thermo-mechanical processes (such as high-temperature straightening) and formulations rich in film-forming agents (including silicones and polymers) and lipids that enhance cuticle cohesion. Associated hair care routines also aim to preserve the structural integrity of the fibre by minimising oxidative and thermal damage. As such, “glass hair” can be considered both a visual indicator of hair health and a key marker in shine-related research.
In this context, Eurofins Cosmetics and Personal Care has developed a dedicated method to quantify the “mirror-like” component of light reflected by the hair fibre, namely its specular shine. This measurement, performed along the entire length of hair tresses, enables precise characterisation of the “glass hair” effect and supports innovation in products designed to enhance shine, smoothness and hair repair.