5 research outputs found
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UV laser radiation for microstructuring of photostructurable glasses
Photostructurable glasses are important materials for applications in microsystems. They enable structures with high aspect ratios and a high dependability of mechanical, optical and chemical properties in a large range of temperatures. The exposure of photostructurable glasses to UV laser radiation, as a rapid prototyping technique, is an alternative method to the exposure by a mask aligner.
Α photostructurable glass (FS21) was exposed to UV laser radiation of the wavelengths 248, 308 and 355 nm. Investigated was the influenee of the exposure parameters wavelength of laser radiation and energy density on structuring results such as crystallization depth, lateral geometry of crystallized areas, structure of crystallized areas and etch angle for single pulse exposure
Raman spectra of Martian glass analogues: A tool to approximate their chemical composition
International audienceRaman spectrometers will form a key component of the analytical suite of future planetary rovers intended to investigate geological processes on Mars. In order to expand the applicability of these spectrometers and use them as analytical tools for the investigation of silicate glasses, a database correlating Raman spectra to glass composition is crucial. Here we investigate the effect of the chemical composition of reduced silicate glasses on their Raman spectra. A range of compositions was generated in a diffusion experiment between two distinct, iron-rich end-members (a basalt and a peralkaline rhyolite), which are representative of the anticipated compositions of Martian rocks. Our results show that for silica-poor (depolymerized) compositions the band intensity increases dramatically in the regions between 550-780 cm À1 and 820-980 cm À1. On the other hand, Raman spectra regions between 250-550 cm À1 and 1000-1250 cm À1 are well developed in silica-rich (highly polymerized) systems. Further, spectral intensity increases at ~965 cm À1 related to the high iron content of these glasses (~7-17 wt % of FeO tot). Based on the acquired Raman spectra and an ideal mixing equation between the two end-members we present an empirical parameterization that enables the estimation of the chemical compositions of silicate glasses within this range. The model is validated using external samples for which chemical composition and Raman spectra were characterized independently. Applications of this model range from microanalysis of dry and hydrous silicate glasses (e.g., melt inclusions) to in situ field investigations and studies under extreme conditions such as extraterrestrial (i.e., Mars) and submarine volcanic environments