In one aspect, a method for use in preparing a glass includes performing an ion exchange process by treating the glass with a eutectic mixture including at least a first rubidium salt. In another aspect, a glass is prepared at least in part by performing an ion exchange process by treating the glass with a eutectic mixture including at least a first rubidium salt.

In one aspect, a method for use in preparing a glass includes performing an ion exchange process by treating the glass with a eutectic mixture including at least a first rubidium salt. In another aspect, a glass is prepared at least in part by performing an ion exchange process by treating the glass with a eutectic mixture including at least a first rubidium salt.

A feed-through element for harsh environments is provided that includes a support body with at least one access opening, in which at least one functional element is arranged in an electrically insulating fixing material. The electrically insulating fixing material contains a glass or a glass ceramic with a volume resistivity of greater than 1.010.sup.10 cm at the temperature of 350 C. The glass or a glass ceramic has a defined composition range in the system SiO.sub.2B.sub.2O.sub.3-MO.

A feed-through element for harsh environments is provided that includes a support body with at least one access opening, in which at least one functional element is arranged in an electrically insulating fixing material. The electrically insulating fixing material contains a glass or a glass ceramic with a volume resistivity of greater than 1.010.sup.10 cm at the temperature of 350 C. The glass or a glass ceramic has a defined composition range in the system SiO.sub.2B.sub.2O.sub.3-MO.

A feed-through element for harsh environments is provided that includes a support body with at least one access opening, in which at least one functional element is arranged in an electrically insulating fixing material. The electrically insulating fixing material contains a glass or a glass ceramic with a volume resistivity of greater than 1.010.sup.10 cm at the temperature of 350 C. The glass or a glass ceramic has a defined composition range in the system SiO.sub.2B.sub.2O.sub.3-MO.

In one aspect, a method for use in preparing a glass comprises: performing a first ion exchange process to replace at least a first ion in the glass with at least a second ion, the second ion being smaller than the first ion; and performing a second ion exchange process to replace at least the second ion in the glass with at least a third ion, the third ion being larger than the first ion. In another aspect, a glass is prepared at least in part by: performing a first ion exchange process to replace at least a first ion in the glass with at least a second ion, the second ion being smaller than the first ion; and performing a second ion exchange process to replace at least the second ion in the glass with at least a third ion, the third ion being larger than the first ion.

In one aspect, a method for use in preparing a glass includes performing an ion exchange process by treating the glass with a eutectic mixture including at least a first rubidium salt. In another aspect, a glass is prepared at least in part by performing an ion exchange process by treating the glass with a eutectic mixture including at least a first rubidium salt.

In one aspect, a method for use in preparing a glass includes performing an ion exchange process by treating the glass with a eutectic mixture including at least a first rubidium salt. In another aspect, a glass is prepared at least in part by performing an ion exchange process by treating the glass with a eutectic mixture including at least a first rubidium salt.

In one aspect, a method for use in preparing a glass comprises: performing a first ion exchange process to replace at least a first ion in the glass with at least a second ion, the second ion being smaller than the first ion; and performing a second ion exchange process to replace at least the second ion in the glass with at least a third ion, the third ion being larger than the first ion. In another aspect, a glass is prepared at least in part by: performing a first ion exchange process to replace at least a first ion in the glass with at least a second ion, the second ion being smaller than the first ion; and performing a second ion exchange process to replace at least the second ion in the glass with at least a third ion, the third ion being larger than the first ion.

In one aspect, a method for use in preparing a glass comprises: performing a first ion exchange process to replace at least a first ion in the glass with at least a second ion, the second ion being smaller than the first ion; and performing a second ion exchange process to replace at least the second ion in the glass with at least a third ion, the third ion being larger than the first ion. In another aspect, a glass is prepared at least in part by: performing a first ion exchange process to replace at least a first ion in the glass with at least a second ion, the second ion being smaller than the first ion; and performing a second ion exchange process to replace at least the second ion in the glass with at least a third ion, the third ion being larger than the first ion.