The invention relates to a method to derive a medical form body of lithium silicate glass ceramic. To increase its strength it is proposed that in the form body comprising lithium silicate glass or containing lithium silicate glass the lithium ions are replaced by alkali ions of greater diameter to generate a surface compressive stress. To this end the form body is covered with a melt containing an alkali metal for which an aliquoted quantity of salt containing the alkali metal is used.

A method of manufacturing a polarizing glass sheet includes subjecting, while heating, a glass preform sheet containing metal halide particles to down-drawing, to thereby provide a glass member having stretched metal halide particles dispersed in an aligned manner in a glass matrix, and subjecting the glass member to reduction treatment to reduce the stretched metal halide particles, to thereby provide a polarizing glass sheet. A shape of the glass preform sheet during the down-drawing satisfies a relationship of the following expression:
L.sub.1/W.sub.1≥1.0
where L.sub.1 represents a length between a portion in which a width of the glass preform sheet has changed to 0.8 times an original width and a portion in which the width of the glass preform sheet has changed to 0.2 times the original width W.sub.0, and W.sub.1 represents a length equivalent to 0.5 times the original width W.sub.0 of the glass preform sheet.

To provide glass including a colored layer and a manufacturing method thereof.

Provided is glass containing one or more glass components selected from the group consisting of Ti ions, Nb ions, W ions, and Bi ions. The glass includes a colored layer having an arbitrary shape.

In order to improve the behaviour of a museum display case towards objects exhibited therein, the display case is subjected to a heat treatment in which the museum display case is maintained at a treatment temperature for a treatment time. The treatment temperature is between 35° and 50° and the treatment time is at least 30 hours. In this way, the emission of harmful volatile substances, including VOCs (volatile organic compounds), is drastically reduced and consequently the objects displayed in the display case are not at risk of damages due to the presence of these volatile substances in the display case.

In order to improve the behaviour of a museum display case towards objects exhibited therein, the display case is subjected to a heat treatment in which the museum display case is maintained at a treatment temperature for a treatment time. The treatment temperature is between 35° and 50° and the treatment time is at least 30 hours. In this way, the emission of harmful volatile substances, including VOCs (volatile organic compounds), is drastically reduced and consequently the objects displayed in the display case are not at risk of damages due to the presence of these volatile substances in the display case.

A conductive composition has excellent adhesiveness and conductivity. A conductive composition contains copper powder, cuprous oxide, a lead-free glass frit, and an acid-based additive. The lead-free glass frit is contained in an amount of 9 to 50 parts by mass relative to 100 parts of the copper powder. The lead-free glass frit contains a borosilicate zinc-based glass frit and a vanadium zinc-based glass frit. The borosilicate zinc-based glass frit contains boron oxide, silicon oxide, zinc oxide, and optional other components, among which boron oxide, silicon oxide, and zinc oxide serve as top-three oxide components in terms of content. The vanadium zinc-based glass frit contains vanadium oxide, zinc oxide, and optional other components, among which vanadium oxide and zinc oxide serve as top-two oxide components in terms of content. The acid-based additive is contained 0.1 to 5.0 parts by mass relative to 100 parts of the copper powder.

A conductive composition has excellent adhesiveness and conductivity. A conductive composition contains copper powder, cuprous oxide, a lead-free glass frit, and an acid-based additive. The lead-free glass frit is contained in an amount of 9 to 50 parts by mass relative to 100 parts of the copper powder. The lead-free glass frit contains a borosilicate zinc-based glass frit and a vanadium zinc-based glass frit. The borosilicate zinc-based glass frit contains boron oxide, silicon oxide, zinc oxide, and optional other components, among which boron oxide, silicon oxide, and zinc oxide serve as top-three oxide components in terms of content. The vanadium zinc-based glass frit contains vanadium oxide, zinc oxide, and optional other components, among which vanadium oxide and zinc oxide serve as top-two oxide components in terms of content. The acid-based additive is contained 0.1 to 5.0 parts by mass relative to 100 parts of the copper powder.

Glass ceramics having SiO.sub.2 as main crystal phase and precursors thereof are described which are characterized by very good mechanical and optical properties and in particular can be used as restoration material in dentistry.

Glass ceramics having SiO.sub.2 as main crystal phase and precursors thereof are described which are characterized by very good mechanical and optical properties and in particular can be used as restoration material in dentistry.

A conductive composition has excellent adhesiveness to a substrate and conductivity. For example, a conductive composition contains copper powder, cuprous oxide, a lead-free glass frit, and a carboxylic acid-based additive. The cuprous oxide is contained in an amount of at least 5.5 parts by mass and up to 25 parts by mass relative to 100 parts by mass of the copper powder. The lead-free glass frit contains a borosilicate zinc-based glass frit and a vanadium zinc-based glass frit. The borosilicate zinc-based glass frit contains boron oxide, silicon oxide, zinc oxide, and optional other components, among which boron oxide, silicon oxide, and zinc oxide serve as top-three oxide components in terms of content. The vanadium zinc-based glass frit contains vanadium oxide, zinc oxide, and optional other components, among which vanadium oxide and zinc oxide serve as top-two oxide components in terms of content.