Comparative study of photo-induced variations of X-ray diffraction and refractive index in photo-thermo-refractive glass

• Published in: Journal of non-crystalline solids 2003-01, Vol.325 (1), p.275-281
• Main Authors: Cardinal, T, Efimov, O.M, Francois-Saint-Cyr, H.G, Glebov, L.B, Glebova, L.N, Smirnov, V.I
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Glasses, quartz; Material chemistry; Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity); Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical materials; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Optics; Physics
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/S0022-3093(03)00310-7

Spontaneous and photo-induced crystallization have been investigated in fluorinated silicate glass by means of X-ray diffraction and optical interferometry. This glass is a photo-sensitive material for high-efficiency phase volume hologram recording. Variations of a refractive index in this glass are controlled by UV irradiation followed by a thermal development which is photo-thermo-refractive (PTR) process. A method of discrimination of weak narrow crystalline lines from a broad diffractive pattern of a vitreous material was developed, and quantitative measurements of small concentrations of crystalline phase in glass matrix were performed. The sensitivity of the method was about 0.01 wt% of crystalline phase of NaF in a silicate glass. This crystalline phase with concentration below 0.1 wt% was detected even in a highly transparent PTR glass with a modified refractive index produced by PTR processing. A correlation between the intensity of X-ray diffraction peaks of NaF and the induced refractive index was found in equally developed PTR glass samples exposed to different dosages of UV radiation.