1/λ~4 scattering of light during the drying process in porous Vycor glass with nano-sized pores

摘要

Porous Vycor glass with nano-sized pores is transparent in the visible region and is often used in colorimetric chemical sensing, when it is impregnated with selectively reacting reagents. However, it has some disadvantages in its use, since changes in the humidity of ambient air strongly affect the transmission. In this work, we analyzed the transparency change during the drying process to correlate the turbidity of the glass with the amount of water in it. The transparency change in the visible region takes place for the duration of the drying and is found to be dependent on the inverse 4th power of the wavelength (1/λ~4), which implies that Rayleigh-type scattering takes place during the drying process. Based on the above observation, it is shown that the transitory white turbidity of nanoporous glasses during the drying process can be interpreted consistently and quantitatively analyzed by a simple Rayleigh scattering mechanism.