Designation:C657−93(Reapproved2013)StandardTestMethodforD-CVolumeResistivityofGlass1ThisstandardisissuedunderthefixeddesignationC657;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationofthedcvolumeresistivityofasmooth,preferablypolished,glassbymeasuringtheresistancetopassageofasmallamountofdirectcurrentthroughtheglassatavoltagehighenoughtoassureadequatesensitivity.Thiscurrentmustbemeasuredundersteady-stateconditionsthatisneitherachargingcurrentnoraspace-charge,builduppolarizationcurrent.1.2Thistestmethodisintendedforthedeterminationofresistivitieslessthan1016Ω·cminthetemperaturerangefrom25°Ctotheannealingpointoftheglass.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.Forspecifichazardstatements,seeSection5.2.ReferencedDocuments2.1ASTMStandards:2D257TestMethodsforDCResistanceorConductanceofInsulatingMaterialsD374TestMethodsforThicknessofSolidElectricalInsu-lation(Withdrawn2013)3D1711TerminologyRelatingtoElectricalInsulationD1829TestMethodforElectricalResistanceofCeramicMaterialsatElevatedTemperatures(Withdrawn2001)33.SummaryofTestMethod3.1ThedcvolumeresistanceismeasuredinaccordancewithTestMethodsD257,withthespecimenlocatedinaheatingchamberwithadequatetemperaturecontrol,electricalshieldingandinsulationofthesampleleadsasdescribedinTestMethodD1829.4.SignificanceandUse4.1Thisexperimentalprocedureyieldsmeaningfuldataforthedcvolumeresistivityofglass.Itisdesignedtominimizespacecharge,builduppolarizationeffects,andsurfaceconduc-tances.Thetemperaturerangeislimitedtoroomtemperaturetotheannealingpointofthespecimenglass.5.Cautions5.1T...
