Provided is a synthetic quartz glass substrate for use in a microfluidic device to which bonding by optical contact can be applied in manufacturing a microfluidic device, and which has high adhesion in a bonded interface and does not cause defects such as non-bonding and breakage of the substrate and a defect in which air bubbles are sandwiched at the bonded interface.

A synthetic quartz glass substrate for use in a microfluidic device, wherein a maximum value of a cyclic average power spectral density at a spatial frequency of 0.4 mm.sup.−1 or more and 100 mm.sup.−1 or less is 5.0×10.sup.15 nm.sup.4 or less, the maximum value being obtained by measuring any given region of 6.0 mm×6.0 mm on a surface of the synthetic quartz glass substrate with a white interferometer.

Crystals having a modified regular tetrahedron shape are provided. Crystals preferably have four substantially identical triangular faces that define four truncated vertices and six chamfered edges. The six chamfered edges can have an average length of l, and an average width of w, and 8≦l/w≦9.5.

Crystals having a modified regular tetrahedron shape are provided. Crystals preferably have four substantially identical triangular faces that define four truncated vertices and six chamfered edges. The six chamfered edges can have an average length of l, and an average width of w, and 8≦l/w≦9.5.

A method for the production of synthetic quartz glass using a special cleaning device is provided. The method includes (a) evaporating a production material containing a polymerizable polyalkylsiloxane compound while forming a production material vapor, (b) passing the production material vapor resulting from step (a) through a cleaning device to purify the production material vapor, (c) supplying the purified production material vapor resulting from step (b) to a reaction zone in which the purified production material vapor is converted to SiO.sub.2 particles through oxidation and/or through hydrolysis, (d) depositing the SiO.sub.2 particles resulting from step (c) on a deposition surface, and optionally drying and vitrifying the deposited SiO.sub.2 particles resulting from step (d) to form synthetic quartz glass. The cleaning device includes a bulk of porous silica particles which have a BET specific surface area of at least 2 m.sup.2/g. A device for carrying out the method is also provided.

A method for the production of synthetic quartz glass using a special cleaning device is provided. The method includes (a) evaporating a production material containing a polymerizable polyalkylsiloxane compound while forming a production material vapor, (b) passing the production material vapor resulting from step (a) through a cleaning device to purify the production material vapor, (c) supplying the purified production material vapor resulting from step (b) to a reaction zone in which the purified production material vapor is converted to SiO.sub.2 particles through oxidation and/or through hydrolysis, (d) depositing the SiO.sub.2 particles resulting from step (c) on a deposition surface, and optionally drying and vitrifying the deposited SiO.sub.2 particles resulting from step (d) to form synthetic quartz glass. The cleaning device includes a bulk of porous silica particles which have a BET specific surface area of at least 2 m.sup.2/g. A device for carrying out the method is also provided.

A method for producing a pore-containing opaque quartz glass includes: (a) producing porous SiO.sub.2 granulate particles from synthetically produced SiO.sub.2, (b) thermally densifying the SiO.sub.2 granulate particles to form partly densified SiO.sub.2 granulate particles, (c) forming a dispersion from the partly densified SiO.sub.2 granulate particles, (d) comminuting the partly densified SiO.sub.2 granulate particles to form a slip containing comminuted SiO.sub.2 granulate particles, (e) shaping the slip into a shaped body and forming a porous SiO.sub.2 green body with a green density rG, and (f) sintering the SiO.sub.2 green body into opaque quartz glass. To produce opaque quartz glass that is also suited for the use of spray granulate, during step (b), partly densified SiO.sub.2 granulate particles are produced with a specific surface BET-(A) between 0.025 and 2.5 m.sup.2/g, and during step (d), comminuted SiO.sub.2 granulate particles are produced with a specific surface BET-(B) between 4 and 10 m.sup.2/g.

A method for producing a pore-containing opaque quartz glass includes: (a) producing porous SiO.sub.2 granulate particles from synthetically produced SiO.sub.2, (b) thermally densifying the SiO.sub.2 granulate particles to form partly densified SiO.sub.2 granulate particles, (c) forming a dispersion from the partly densified SiO.sub.2 granulate particles, (d) comminuting the partly densified SiO.sub.2 granulate particles to form a slip containing comminuted SiO.sub.2 granulate particles, (e) shaping the slip into a shaped body and forming a porous SiO.sub.2 green body with a green density rG, and (f) sintering the SiO.sub.2 green body into opaque quartz glass. To produce opaque quartz glass that is also suited for the use of spray granulate, during step (b), partly densified SiO.sub.2 granulate particles are produced with a specific surface BET-(A) between 0.025 and 2.5 m.sup.2/g, and during step (d), comminuted SiO.sub.2 granulate particles are produced with a specific surface BET-(B) between 4 and 10 m.sup.2/g.

Disclosed herein are glass-ceramics having crystalline phases including β-spodumene ss and either (i) pseudobrookite or (ii) vanadium or vanadium containing compounds so as to be colored and opaque glass-ceramics having coordinates, determined from total reflectance—specular included—measurements, in the CIELAB color space of the following ranges: L*=from about 20 to about 45; a*=from about −2 to about +2; and b*=from about −12 to about +1. Such CIELAB color space coordinates can be substantially uniform throughout the glass-ceramics. In each of the proceeding, β-quartz ss can be substantially absent from the crystalline phases. If present, β-quartz ss can be less than about 20 wt % or, alternatively, less than about 15 wt % of the crystalline phases. Also Further crystalline phases might include spinel ss (e.g., hercynite and/or gahnite-hercynite ss), rutile, magnesium zinc phosphate, or spinel ss (e.g., hercynite and/or gahnite-hercynite ss) and rutile.

Disclosed herein are glass-ceramics having crystalline phases including β-spodumene ss and either (i) pseudobrookite or (ii) vanadium or vanadium containing compounds so as to be colored and opaque glass-ceramics having coordinates, determined from total reflectance—specular included—measurements, in the CIELAB color space of the following ranges: L*=from about 20 to about 45; a*=from about −2 to about +2; and b*=from about −12 to about +1. Such CIELAB color space coordinates can be substantially uniform throughout the glass-ceramics. In each of the proceeding, β-quartz ss can be substantially absent from the crystalline phases. If present, β-quartz ss can be less than about 20 wt % or, alternatively, less than about 15 wt % of the crystalline phases. Also Further crystalline phases might include spinel ss (e.g., hercynite and/or gahnite-hercynite ss), rutile, magnesium zinc phosphate, or spinel ss (e.g., hercynite and/or gahnite-hercynite ss) and rutile.

One aspect relates to a method for the production of synthetic quartz glass. Moreover, one aspect relates to a polyalkylsiloxane compound, which includes certain specifications with respect to chlorine content, metallic impurities content, and residual moisture, as well as the use thereof for the production of synthetic quartz glass. One aspect also relates to a synthetic quartz glass that can be obtained according to the method of one embodiment.