Near-infrared-transparent materials

The attenuated total reflectance (ATR) technique is used commonly in the near-infrared for obtaining absorption spectra of thin Aims and opaque materials. The sample, of refractive index i, is placed in direct contact with a material which is transparent in the region of interest, such as thallium bromide/thallium iodide (known as KRS-5), silver chloride or germanium, of relatively high refractive index so that Then, as Figure 3.f8... 

Conversely, in the summer, it would still have a high transparency for the visible, but a high reflectivity for the near infrared and a high emissivity for the far infrared. The present state of the art of thin-films deposition still falls short of this goal which may have to wait for the development of suitable photochromic coating materials. 

Changes of fibre optical properties and thus changes of the analyte can be detected in the ultraviolet (UV), visible (VIS), near infrared (NIR) and middle/far infrared (IR) regions. There are only a few materials sufficiently transparent in the UV region, and among them, the pure silica is uniquely suitable for fibre drawing. From Figure 5 it can be seen that the UV... 

The phosphazene backbone also possesses unusual features that lead to a range of potential applications for these easily processed materials (Figure For example, it is extremely flexible and polyalkoxypho-sphazenes such as the -butoxy derivative [P(0"Bu)2=N] possess glass transition temperatures Tg of below -100 Furthermore, the P-N main chain is thermally and oxidatively stable, optically transparent from 220 nm to the near-infrared region and it imparts flame-retardant properties. 

Sumida et al. (4) prepared cyclic polymerizable florinated norbomane monomers, (VII), suitable for photoresist materials which had high transparency in the light wavelength region from ultraviolet to near-infrared. 

Starting materials with alumina contents near the stoichiometry of 2 1 mullite may be completely melted above 1,960°C and then cooled to about 1,890°C without crystallizing. At the latter temperature (in the shifted solid solution region), infrared-transparent mullite single crystals could be grown by the Czochralski method [32],... 

The value of computing derivative spectra to correct for non-linear baseline signals is frequently exploited in reflectance spectrometry. Rapid measurement of the chemical composition of materials and products by diffuse reflectance spectroscopy in the near-infrared (NIR) region (800-2600 nm) is routine in many industries. Because most bulk materials are not transparent the mode of measurement is generally reflectance. For powder samples the intensity of... 

---