ISO 21575:2018

ISO 21575:2018(E)

INTERNATIONAL STANDARD
ISO
Deleted: /FDIS
21575
Deleted: :
First edition
2018-06 Deleted: (E)


Deleted: ISO/TC 172/SC 3/WG 1¶
Optics and photonics — Optical materials and components
— The powder test method for the water resistance of
optical glass
Optique et photonique — Matériaux et composants optiques — Méthode d'essai sur poudre pour Deleted: Élément introductif —
Élément central — Élément
déterminer la résistance à l'eau des verres optiques
complémentaire¶
© ISO 2018 – All rights reserved
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ISO/FDIS 21575:2018(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national
standards bodies (ISO member bodies). The work of preparing International Standards is normally
carried out through ISO technical committees. Each member body interested in a subject for which a
technical committee has been established has the right to be represented on that committee.
International organizations, governmental and non‐governmental, in liaison with ISO, also take part in
the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all
matters of electrotechnical standardization.
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described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Deleted: ).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents). Deleted: ).
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World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: www.iso.org/iso/foreword.html. Deleted: .
This document was prepared by Technical Committee ISO/TC 172, Optics and photonics,
Subcommittee SC 3, Optical materials and components.
© ISO 2018 – All rights reserved
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ISO 21575:2018(E)
Introduction
There are two commonly used methods for measurement of the chemical resistance of optical glass:
The powder method and the surface method. The powder method has simpler procedures for the
sample preparation since it does not require a homogeneously polished surface.
© ISO 2018 – All rights reserved
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FINAL DRAFT INTERNATIONAL STANDARD ISO 21575:2018(E)

Optics and photonics — Optical materials and components —
The powder test method for the water resistance of optical
glass
1 Scope
This document specifies the general procedures of the powder test method for the water resistance of
optical glass.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3310‐1, Test sieves — Technical requirements and testing — Part 1: Test sieves of metal wire cloth
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 4797, Laboratory glassware — Boiling flasks with conical ground joints
ISO 4799, Laboratory glassware — Condensers
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
4 Principles
The glass is ground into particles of diameter within the range of 425 µm to 600 µm. A powder sample Deleted: The powdered
equivalent to the specific gravity in grams is placed in a platinum basket. The basket is placed in a flask
of silica glass and boiled for 60 min. The degree of water resistance is determined by measuring the
weight loss (in percent), and is denoted by a class number ranging from 1 to 6, as given in Table 1.
5 Reagents
5.1 Water
The purity of the water used shall comply with the grade 2 requirements of ISO 3696.
...