POROUS SILICA, OPTICAL-PURPOSE LAYERED PRODUCT AND COMPOSITION, AND METHOD FOR PRODUCING POROUS SILICA

摘要

A porous silica having a low refractive index and being stable when exposed to water, and which is configured to have a refractive index of 1.3 or lower and to have a difference of the refractive index at a wavelength 550 nm between before the immersion into water and after the immersion into water for 24 hours of 0.15 or lower.