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GB/T 7962 Test methods of colorless optical glass include 23 parts as follows:
—— Part 1: Refractive index and coefficient of dispersion;
—— Part 2: Optical homogeneity—Fizeau plano-interferometry;
—— Part 3: Optical homogeneity—Holographic interferometry;
—— Part 4: Temperature coefficient of refractive index;
—— Part 5: Stress birefringence;
—— Part 6: Young’s modulus, shear modulus and Poisson’s ratio;
—— Part 7: Extent of stria;
—— Part 8: Bubble;
—— Part 9: Coefficient of optical absorption;
—— Part 10: X-rays stability;
—— Part 11: Precise test method for refractive index in the visible wave band;
—— Part 12: Spectral internal transmittance;
—— Part 13: Coefficient of thermal conductivity;
—— Part 14: Resistance to acid;
—— Part 15: Resistance to humidity;
—— Part 16: Linear thermal expansion coefficient, transformation temperature and yield point temperature;
—— Part 17: Autocollimation test method for refractive index in the ultraviolet and infrared wave band;
—— Part 18: Knoop hardness;
—— Part 19: Abrasion factor
—— Part 20: Density;
—— Part 21: Resistance to attack by aqueous alkaline solutions;
—— Part 22: Resistance to attack by aqueous alkaline phosphate-containing;
—— Part 23: Resistance to climatic;
This document is Part 21 of GB/T 7962.
This standard is developed according to the rules stipulated in GB/T 1.1-2009.
This standard is redrafted by modifying ISO 10629:1996 Raw optical glass—Resistance to attack by aqueous alkaline solutions at 50℃—Test method and classification.
Compared with ISO 10629:1996, this standard has made a lot of adjustments in structure. Annex A lists the differences of section and article numbers of this standard and ISO 10629:1996.
Technical differences between this standard and ISO 10629:1996, and the reasons for such modifications are as follows:
—— As for normative references, technical revisions are made to adapt to China's technical conditions, which is reflected in Section 2, "Normative References", with specific revisions as follows:
• ISO 2768-1: 1989 is replaced by GB/T 1804-2000 as it adopts and is equivalent with this international standard;
• ISO 3696:1987 is replaced by GB/T 6682-2008 which adopts this international standard with modification;
• ISO 3585:1991 is removed;
• GB/T 903 and GB/T 1185-2006 are added.
—— "2-propanol" is changed to "isopropyl alcohol" (as they are the same substance judged according to their molecular formula and properties, therefore a unified Chinese name is used).
—— 6.1 Material requirements (to reduce differences in test results caused due to material difference) is added to Section 6.
—— The fine grinding and polishing requirements in 6.1 of ISO 10629:1996 are adopted as 6.2 Quality requirements (for convenient standard implementation);
—— Measurement accuracy of dimension in 6.3 is modified (so as to reduce the difference in surface area of the test samples).
—— The content of Section 7 is renumbered and modified according to test requirements and test procedure, and tolerance is added (so as to facilitate the implementation of the standard).
—— Optical glass alkaline resistance classes based on 1st decimal point are tabularized, and a test report form is added.
The following editorial changes have been made to this standard:
—— modify the standard name as “Test methods of colorless optical glass—Part 21: Resistance to attack by aqueous alkaline solutions”;
—— add the informative Annex A.
Attention is drawn to the possibility that some of the elements of this document may be in the subject of patent rights. The publishing institute shall not be held responsible for identifying any or all such patent rights.
This standard is proposed by China Machinery Industry Federation.
This standard is under the jurisdiction of National Technical Committee of Optics and Photonics (SAC/TC 103), Standardization Administration of China.
The drafting units of this standard include: CDGM GLASS Co., Ltd., China Ordnance Industrial Standardization Research Institute, Chinese Academy of Sciences/Shanghai Institute of Optics and Fine Mechanics
The main drafters of this standard include: Zhou Huimin, Zhou Quanquan, Liu Xiaodong, Su Yong, Li Weina, Hu Junjiang
Test Methods of Colorless Optical Glass—
Part 21: Resistance to Attack by Aqueous Alkaline Solutions
无色光学玻璃测试方法 第21部分:耐碱稳定性
1 Scope
This part of GB/T 7962 specifies the principle, procedure, data processing and classification of resistance stability of colorless optical glasses to aqueous alkaline solutions.
This standard is applicable to colorless optical glasses, and it may be used for other types of glasses.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated reference, only the dated edition is applicable to this Standard. For undated reference, the latest edition (including all corrigenda) referred to is applicable to this Standard.
GB/T 903 Colorless optical glass
GB/T 1185-2006 Surface imperfections of optical elements
GB/T 1804-2000 General tolerances—Tolerances for linear and angular dimensions without individual tolerance indications (eqv ISO 2768-1:1989)
GB/T 6682-2008 Water for analytical laboratory use—Specification and test methods (ISO 3696: 1987, MOD)
3 Principle
Attack on polished test sample by an aqueous solution containing 0.01 mol/L sodium hydroxide at 50 °C for specified time. Weighing to determine the loss in mass and calculation of depth of attack based on the density of the glass. Comparison of the time, t0.1, required for the apparent attack to and stopper is continually depth of 0.1 μm with time scales given in a classification table to obtain the alkali resistance class of the tested glass.
4 Reagents
4.1 General
During the test, unless otherwise specified, use only reagents of recognized analytical grade.
4.2 Water
It shall comply with the grade 2 requirements specified in GB/T 6682-2008.
4.3 Test solution
Dilute the sodium hydroxide solution with water; control the pH-value and adjust to pH 12 ± 0.1.
4.4 Nitric acid (HNO3)
Analytical grade of nitric acid is diluted to pH = 4.5 ± 0.1.
4.5 Sodium hydroxide solution
The concentration cNaOH≈0.1 mol/L.
4.6 Isopropyl alcohol (C3H7OH)
No residue shall be visible after evaporation.
5 Apparatus
5.1 Stirrer
The stirrer is made of stainless steel or polytetrafluoroethylene (PTFE). The rod length of stainless steel stirrer is (350.0 ± 2.5) mm, with a diameter of (10.0 ± 1.0) mm; the rod length of polytetrafluoroethylene (PTFE) stirrer is (350.0 ± 2.5) mm, with a diameter of (15.0 ± 1.0) mm. The vertical height of the blade cross-section is (15.0 ± 1.0) mm and the width is (58.0 ± 1.0) mm, see Figure 1.
Dimensions in millimeters
a) Stainless steel b) PTFE
Figure 1 Stirrers
5.2 Reaction vessel
Reaction vessel is cylindrical with a flat base, made of stainless steel, having an internal diameter of (150.0 ± 2.5) mm and a height of (200 ± 2.5) mm. The lid and vessel body are fastened with fastening screws and nuts, see Figure 2. The lid has a wide neck, and is equipped on the bottom with two hooks from which to suspend the samples. The neck is filled with a stopper of suitable inert material which has previously been boiled in sodium hydroxide for 60 min, and through which a stirrer can be inserted. Permissible variations in dimensions without tolerance indication shall be in accordance with those for the Level v (very coarse) given in Table 1 of GB/T 1804-2000.
5.3 Platinum or silver wires
Platinum or silver wires with a diameter of less than 0.1 mm are used to hang test samples; or cages of the same material are used to hold test samples.
5.4 Thermostatic bath
Thermostatic bath has a capacity of 30 to 40 liters, and can be thermostatically controlled to maintain the temperature of (50.0 ± 0.2) °C.
5.5 Analytical balance
Analytical balance has a graduation of 0.1 mg.
5.6 Desiccator
Use a silane mixture (for H2O absorption) and soda-lime (a mixture of CaO and Na2O, for CO2 absorption) as desiccants.
5.7 Tongs
Tongs are made of materials that do not damage the smooth surface of the samples, for example, plastics.
5.8 Vernier caliper
Vernier caliper has a minimum graduation of 0.02 mm.
5.9 Ultrasonic equipment
The cleaning tank is filled with water, and can be heated to 50 °C.
5.10 Beakers
Beakers shall have a capacity of 100 mL and 500 mL.
5.11 pH meter
pH meter has a minimum graduation of 0.05.
Foreword i
1 Scope
2 Normative References
3 Principle
4 Reagents
5 Apparatus
6 Preparation of Test Sample
7 Test Procedure
8 Calculation of Results
9 Classification and Designation
10 Test Report
Annex A (Informative) Structural Changes between This Part and ISO 10629: