Related Experiment Video
Updated: Jul 6, 2026

Cooling Rate Dependent Ellipsometry Measurements to Determine the Dynamics of Thin Glassy Films
Published on: January 26, 2016
Adsorption of water on porous Vycor glass studied by ellipsometry
A Alvarez-Herrero1, R L Heredero, E Bernabeu
1Laboratorio de Instrumentación Espacial (LINES), Area de Cargas Utiles e Instrumentación, División de Ciencias de Espacio, Instituto Nacional de Técnica Aeroespacial (INTA), 28850 Torrejón de Ardoz, Madrid, Spain. alvarez@inta.es
Abstract:
The variation of the optical properties of porous Vycor glass (Corning, Model 7930) under different relative-humidity conditions was studied. The adsorption of water into the glass pores was investigated with spectroscopic ellipsometry. The change of the refractive index was Deltan approximately 0.04 between 5% and 90% relative humidity. A linear relation between the ellipsometer parameter tan Psi, the amount of water adsorbed in the glass pores, and information about the pore-size distributions was established. The results are in accord with the values obtained from N2 isotherms, transmission electron microscope micrographs, and the manufacturer's specifications (radius of approximately 20 A). The possibility of using this material as a transducer for implementation in a fiber-optic sensor to measure humidity was evaluated.
Related Concept Videos
Porosity and Absorption of Aggregate
When all pores in an aggregate are filled with water, the aggregate is considered saturated and surface-dry. If left in dry air, water will evaporate until the aggregate...
Volatilization
UV–Vis Spectroscopy: Beer–Lambert Law
Adsorption Isotherms I
Adsorption Isotherms II
UV–Vis Spectroscopy: Woodward–Fieser Rules

