Abstract: A temperature sensing apparatus for use in association with faucets, which dispense liquid mediums, such as water. A thermal transfer element, which may comprise a band-like member, includes an inner surface, an exterior surface and a base color visually observable on at least a portion of the exterior surface. Base color changing material is integrally distributed within the thermal transfer element, and, serves to change at least a portion of the base color to one or more alternative colors. Each alternative color is visually observable upon transfer of a predetermined degree of heat generated from the liquid medium to and through the thermal transfer element. Sensitivity enhancement members, which are integrally formed in the thermal transfer element, facilitate the transfer of the degree of heat so generated from the liquid medium, and, in turn, expedite the changing of the base color of the thermal transfer element to the one or more alternative colors.

Abstract: A method and apparatus for measuring the core body temperature of infants or persons without volitional bladder control utilizing minimal urine volume. The device employs a readily deployed collection surface contiguous with a sump or reservoir into which the collected urine contacts a superabsorbent powder. Affixed to the reservoir is a peak temperature sensor for indicating the maximum temperature of the urine and thereby the core body temperature of the donor.

Abstract: A dual temperature indicator providing visual indications when exposed to predetermined high or low temperatures. The indicator has a bulb with a capillary tube and an attached high temperature indicator structure. The bulb has a first liquid which also fills a predetermined portion of the tube. A separating substance and a second miscible liquid further fills a predetermined portion of the remainder of the tube. At a predetermined low temperature, the liquid in the bulb contracts causing the separating substance and a portion of the second liquid to move into the bulb to produce a visible color change. The high temperature indicator structure has an indicating member in contact with the capillary tube end and which provides a visual indication at a predetermined high temperature when the liquids expand upon an environmental temperature increase.

Abstract: A measuring system measures temperature distribution in water using an optical fiber. An optical fiber cable suspended from a ship and towed by the ship to form an arch within the water. A measuring device for continuously measuring temperature at various points along the lengths of said optical fiber cable. Sensors are provided within the water to calculate the water depth at each of the various points along the length of the arch shaped optical fiber. Thus, a temperature distribution at each water depth can be continuously measured.

Abstract: An optical sensor has a photosensitive portion which has a first layer including oxo metallic phthalocyanine pigment and a second layer consisting of organic polysilane and shows a sensing of light with a change of color. The optical sensor can also be used as a thermal sensor.

Abstract: A dressing having a skin or wound contacting surface is provided with an indicator means on the opposite surface. The indicator means is capable of sensing the condition of the skin or wound underlying the dressing and conveying the information to the health care professional eliminating the need to frequently change the dressing.

Abstract: An inorganic thermochromic substance is proposed which is a composite oxide of strontium and manganese in a specified molar ratio as prepared by the calcination of a powder blend of strontium carbonate and manganese dioxide, instead of conventional manganese carbonate, at a specified temperature for a specified length of time. The temperature of the thermochromic color change is about -130.degree. C., much lower than the color-change point of most of conventional thermochromic substances. The color of the composite oxide is grey or pale green at room temperature but reversibly changes to pale red when it is chilled to -130.degree. C. or lower.

Abstract: A method of making and using a liquid crystal cumulative dosimeter container including a resilient outer body sealed to confine a first liquid crystal composition constituent and a second liquid crystal composition constituent and having at least one transparent section to permit observation of the color of the confined composition, and a barrier contained completely within and physically unattached to the outer body for separating the first constituent from the second constituent, whereby disruption of the barrier allows the first constituent to mix with the seocnd constituent. The barrier is formed either by encapsulating one or both of the constituents or by using air bubbles.

Abstract: Hand grips for the handles of devices such as motorcycles, tennis rackets, and guns can be custom-molded to fit exactly the contours of the user's hand. The grip has an inner layer that is thermoplastic and moldable at molding temperatures reached by heating with hot water or a hair dryer. An adherent outer, resilient, vibration-resistant layer is stable at these molding temperatures. The user heats the grip to molding temperature and then rapidly cools the outer surface to a comfortable temperature. The grip is then grasped by the hand while the inner layer is still at molding temperature. The hot inner layer conforms to the hand, becoming thinner under the fingers and thicker between fingers. The grip is cooled to ambient temperature and the inner layer retains its hand-conforming shape. The outer layer maintains its original thickness providing a fixed resilient cushioning layer over the custom formed inner layer.

Abstract: The invention relates to a heat-shrinkable article that is at least partially coated with a temperature indicator. This temperature indicator is composed of an organic polymer having a suitable bonding agent, whereby the organic polymer is contained therein in a finely ground condition. As a result of this condition, the appearance of the agent is opaque and has a color corresponding to the degree of granulation and material constituent. When the melting point of the composition is reached, the material melts and becomes transparent or at least translucent. The color of the article shows through, so that this color change can be interpreted as a temperature indication.

Abstract: A food service process including a hot food dish and an insulated dome. Hot food is served onto the dish, the dome set over the dish, and the dome covered hot food dish is delivered to the intended consumer. A thermochromic member disposed in a heat conductive sleeve is mounted in the lift knob of the dome. Thus, without lifting the dome, the server and/or the consumer can readily determine from the color of the member whether the covered food is still at a safe heating temperature. In an alternative process, the dome is first preheated and then placed over the plate of hot food. Then similarly, after the plated food is transported to a different location and delivered for consumption, the server and/or the consumer can determine from the color of the thermochromic member whether the food is still at a safe temperature for consumption.

Abstract: A method is disclosed for substantially eliminating undercooling in a liquid cooled below its freezing point which comprises utilizing a nucleating agent system comprising:(1) a nucleating agent which is a metal compound, insoluble in the liquid, the metal compound and liquid having similar molecular space groupings; and(2) at least 0.075 wt. % based on the metal compound of a soluble salt of a metal which is the same metal as that of the metal compound.In a preferred embodiment the valence state of the metal of the salt is the same as that of the metal of the metal compound. In another embodiment a metal compound of limited solubility, e.g., less than 1% by weight in the liquid, more preferably about 0.15 to about 0.25 wt. %, is utilized to serve the function of both the insoluble nucleating agent and the soluble metal salt.Where the liquid is water, deuterium oxide or mixtures thereof the preferred metal compound is cupric sulfide and the preferred salt is cupric sulfate.

Abstract: A container for a liquid crystal cumulative dosimeter including a resilient outer body sealed to confine a first liquid crystal composition constituent and a second liquid crystal composition constituent and having at least one transparent section to permit observation of the color of the confined composition, and a barrier contained completely within and physically unattached to the outer body for separating the first constituent from the second constituent, whereby disruption of the barrier allows the first constituent to mix with the second constituent. The barrier is formed either by encapsulating one or both of the constituents or by using air bubbles. Methods of manufacturing the various containers shown and processes of using those containers are also disclosed.

Abstract: Fiberoptic sensors of various configurations are provided for measuring the magnitude of the electric or magnetic fields, and thereby the power, at local points within a relatively high-power electromagnetic heating environment such as occurs, for example, in a microwave oven or an industrial microwave processing chamber. Each type of sensor includes one element that is heated by either the oscillating electric or magnetic field, and an optical temperature measuring element positioned to be heated by the first element, its temperature being optically determined by an instrument to which an opposite end of the optical fiber length is connected.

Abstract: The present invention relates to a method for determining the level of concrete in a concrete mixer comprising the steps of contacting the exterior of concrete mixing drum with a strip of thermal color sensitive material and observing the interface on the color sensitive material produced by the temperature differential between the concrete and the air above. This level can then be lined up horizontally with a graduated volume indicator, to yield the concrete volume in the truck to aid in determining an effective amount of additive to be added to the concrete.

Abstract: A temperature measuring device useful for measuring the temperature of urine samples is disclosed comprising a solid solution having incorporated therein a nucleating agent and an indicating dye system. The preferred solid solution is a mixture of ortho-chloronitrobenzene and ortho-bromonitrobenzene. The preferred dye systems are pinacyanol iodide and a mixture of bromcresol purple and ethyl red. A novel aspect of the thermometer is that it is adapted to indicate a predetermined temperature at an observable initiation of melt temperature which is about 0.3.degree. to about 1.9.degree. F. below the completion of melt temperature of the composition. The thermometer is a real time device.

Abstract: A threaded temperature indicating plug for hot oil containing housings such as vehicle transmissions and the like that can replace the standard oil level plugs of the same and as well afford a plug that from which the temperature at which the oil may have overheated will be recorded and whether there is a definite need to change the oil in the transmission. Liquid crystal areas are provided on an indicator label that is fixed to the plug bolt shank in a liquid-tight manner by a fixed covering and for direct contact with the oil body or a splash from oil at a lowered level.

Abstract: A temperature indicating paint which is generally time independent comprises an organic resin, high temperature glass frit resin and one or more of the following elements; silver, gold, platinum, palladium, copper, nickel, chromium, titanium and silicon, dispersed in 10% to 70%, by weight, of a solvent. The paint is applied to a specimen by brushing or spraying and the specimen is then stoved for 5 minutes at between 750.degree. C. and 850.degree. C.

Abstract: Compositions of matter and methods of preparation are described for water and air stable, square planar transition metal double-complex salts which contain isonitrile ligands derivatized with long chain aliphatic groups. These salts are composed of two metal-containing complex ions: the cation is a tetrakis isonitrile metal ion and the anion is a tetrahalometallate or tetracyanometallate. These double-complex salts exhibit the novel property of thermochromism and are useful as temperature indicators and in imaging applications.

Abstract: A rhinological diagnostic device in the form of a multi-layer sheet comprising, from top to bottom, a transparent plastic layer, a thermochromic liquid crystal layer, a black coating layer and a support layer. In use, this multi-layer sheet is positioned beneath the nose to cause expired air from the nostrils to impinge on the transparent plastic layer for diagnosing an abnormality in the nasal cavity based on the resulting topographic color pattern in said thermochromic liquid crystal layer.

Abstract: A food container for use in a microwave oven is disclosed. The container contains a plurality of food substances, and employs a metal shield to shield at least one of the food substances from microwave radiation. Arcing and other problems associated with the use of metal shielding are avoided by proper selection of the geometry of the metal shield. The metal shield is preferably looped in a manner which provides some electrical inductance, and the ends of the metal shield are overlapped and separated by a dielectric material to provide some electrical capacitance. The geometry of the shield is selected so that the inductance and the capacitance in effect form a "tuned circuit" which minimizes problems associated with resonance and which eliminates arcing.

Abstract: Thermochromic compounds containing the [Pt(dipic)Cl].sup.- anion. These compounds are yellow and monomeric at high temperatures or in low concentrations and abruptly change to red and polymeric at low temperatures or higher solution concentrations. This unusual property allows them to be used as temperature sensors.

Abstract: A photoactivated time-temperature indicator is based on a leuco base system. A thermally insensitive, white ("inactive") leuco base (or a mixture of such leuco bases) is mixed, preferably in a polymeric matrix, with a material that generates acid upon exposure to light. Photoexcitation, preferably by UV or near UV light, causes the formation of a thermally sensitive, color-forming ("active") product. Following this activation step, a progressive color development occurs at a rate that increases with temperature. The indicator is useful for monitoring the freshness of perishable products, particularly those stored at subambient temperature.

Abstract: A microwave oven wattage detector having a visually and microwave transparent container holding a thermally homogeneous fluid having a wattage-indicating strip contained in the fluid with a plurality of different temperature-sensitive areas on the strip with indicia associated with each of the areas to indicate power levels when such container is heated within a microwave oven for a set time and one of such temperature-sensitive areas changes color to denote the indicia indicating the power level of the microwave oven.

Abstract: An inexpensive, compact, portable, visual indicator electrical plug-type surge protector which comprises an electrical plug body composed of a molded transparent polymer, the plug body having an extended male grounding prong and a pair of male electrical prongs on one face and a female receiving grounding inlet and a pair of female receiving inlets on the opposite face. The plug body contains in a visually indicating position, generally slightly below the surface of the plug body, a metal oxide varistor electrically connected to the electrical outlet plug so as to prevent electrical surges from passing through the surge protector from the electrical source into which the electrical plug-type surge protector is plugged and to be activated and to change color on the occurrence of an electrical surge so that the user of the surge protector will know when the electrical surge has been received and thereby be able to replace the surge protector with a new surge protector.

Abstract: A pyrometric temperature measuring instrument including at least one optical wave guide (1a) with a core (5) and a cladding (6), a light detector (3) and at least one pyrometric sensor (2a). The at least one optical wave guide (1a) has a large numerical aperture. The pyrometric sensor (2a) is located at one end of the at least one optical wave guide (1a) and covers at least a cross-section of the core (5) of an optical wave guide (1a). In a preferred embodiment, the light detector (3) is an InGaAs photodiode. The optical wave guide (1a) has a numerical aperture of 0.3 or more, a diameter of the core (5) of approximately 100 .mu.m or more, and is surrounded by a light-tight cover (7).

Abstract: The source and the device comprise a generator of a pump wave, optical means for coupling with a monomode optical fiber for guiding and highly confining the pump wave so that a four photon non linear interaction is created. At least one section of this optical fiber is disposed in a thermostat controlled enclosure associated with a temperature control device so as to obtain continuous tuning in a range of frequencies belonging to the near infra red spectrum.

Abstract: A new process is described which is useful for producing novel articles of manufacture useful for monitoring the time-temperature history of perishable items. The process initially involves forming a solution comprised of a diacetylenic monomer and a solvent. The solution is frozen, and the frozen solution having crystalline diacetylenic monomer therein is irradiated to partially polymerize the diacetylenic monomer. Partial polymerization of the crystalline diacetylenic monomer admixed with frozen solvent results in the production of a novel article of manufacture having color. The novel article of manufacture is comprised of frozen solvent, diacetylenic monomer, and colored polydiacetylene. Due to the intensity of the color of the polydiacetylene, the entire article of manufacture appears to be colored.The colored article of manufacture may be attached to various perishables to monitor the shelf life of the perishables.

Abstract: A thermal imaging system provides quantitative temperature information and is particularly useful in hypersonic wind tunnel applications. An object to be measured is prepared by coating with a two-color, ultraviolet-activated, thermographic phosphor. The colors emitted by the phosphor are detected by a conventional color video camera. A phosphor emitting blue and green light with a ratio that varies depending on temperature is used so that the intensity of light in the blue and green wavelengths detected by the blue and green tubes in the video camera can be compared. Signals representing the intensity of blue and green light at points on the surface of a model in a hypersonic wind tunnel are used to calculate a ratio of blue to green light intensity which provides quantitative temperature information for the surface of the model.

Abstract: A sun heat radiation sensor is provided having a plurality of display areas each of which comprises a different, heat activatable liquid crystal composition. The liquid crystal compositions are selected so that the display areas provide a quantitative visual indication of the sun heat radiation sensed by the sensor. The sensor may be applied to a container for sun-screening substances, e.g. typically to a lid of the container.

Abstract: Described are cholesteric liquid crystal formulations suitable for use as indicators of time and/or temperature, and methods for reliably characterizing and reproducing initial and subsequent batches of such cholesteric liquid crystal formulations. The formulations have a time-dependent, temperature-dependent limit in a pseudo-irreversible liquid crystal phase wherein when said limit is exceeded, the formulations exhibit a color change which is irreversible by cooling.

Abstract: A heating system for heating a rapidly rotating article, including a strobe capable of emitting radiant energy and positioned to radiate energy onto the article, a light source positioned to illuminate a temperature-sensing means on the article, a light detector to measure changes in the light reflected by the temperature-sensor and a control device to energize the strobe in response to reflected light from the detector.

Abstract: A time-temperature integrator based on color changes produced by the chemical reaction between reducing sugars and amino groups (i.e. amino-acids, peptides, proteins) permits the verification of the thermal history during cooking at 85.degree.-100.degree. C. of a hermetically sealed package for inspection and which can not be removed or substituted without breaking the package.

Abstract: Compositions of matter and methods of preparation are described for water and air stable, square planar transition metal double-complex salts which contain isonitrile ligands derivatized with long chain aliphatic groups. These salts are composed of two metal-containing complex ions: the cation is a tetrakis isonitrile metal ion and the anion is a tetrahalometallate or tetracyanometallate. These double-complex salts exhibit the novel property of thermochromism and are useful as temperature indicators and in imaging applications.

Abstract: A series of chemically synthesized compounds known as metal mercury iodides or metal tetraiodomercurates having use as infrared detectors are made by reacting potassium tetraiodomercurate(II) with monovalent metal nitrates or iodides, such as thallium(I), indium(I) or copper(I) nitrates. In the case of gold, the gold(I) iodide is used because the nitrate is not known. The precipitated metal (thallium, indium, copper, gold, etc.) tetraiodomercurate is then filtered, dried, and purified (recrystallized) and pressed into a disk under high pressure. Alternatively, the material can be grown as a large crystal by zone melt fusion methods.

Abstract: A temperature indicating device which comprises a plurality of panels in a fixed array. Some of the panels are adapted to undergo a reversible change in appearance at a given temperature whereas the remainder are adapted to undergo irreversible change in appearance at a given temperature. The device is useful in indicating the temperature which an object has achieved as well as its actual temperature.

Abstract: A liposomal thermograph is employed to monitor the thermal history of goods in transit or storage. The liposomal thermograph becomes fluorescent if the temperature of the goods exceed an operating range. The liposomal thermograph is bi-directional, i.e. it becomes fluorescent if the temperature transgression either falls below a set value on the lower end of the operating range or if it rises toward the upper end of the operating range. The activation of the liposomal thermograph is abrupt at the lower end of operating range. However, at the upper end of the operating range, the liposomal thermograph displays a ramp effect, i.e. the onset of fluorescence is progressive and depends upon the duration of the transgression and the magnitude. The liposomal thermograph is made from a sachet which is filled with a suspension of liposomes which have been loaded with an amphphilic anionic fluorescent dye, preferably having a sodium counterion.

Abstract: A fiber optic core cladded with a material having an index of refraction lower than the core material and light sensing means located along the length of the core and cladding material. The sensing means receives light which escapes into the cladding from the core when the fiber optic is stressed, and produces an output in response to light received. Measurement of the output provides both magnitude and location information with respect to stresses in the fiber optic. A measurement of fiber temperature by detection of dark current, which is the function of temperature, is effected in pixels of the sensing means located in intimate contact with the fiber. An accurate measurement of stress in the fiber is made by subtracting dark current measurements from stress measurements when the fiber optic is excited with light.

Abstract: An activatable time-temperature indicator consists of an oxygen-sensitive reaction product of a triarylmethane dye and a decolorant that is coated on a substrate and covered by an oxygen barrier. Optinally, an oxygen-permeable layer is between the coating and the oxygen barrier. The indicator is activated by removing the oxygen barrier. Following this activation step, a progressive color development occurs at a rate that increases with temperature. The indicator is useful for monitoring the freshness of perishable products, particularly those stored at sub-ambient temperature.

Abstract: A time-temperature indicator, particularly adapted for use with closed sterilizing or cooking vessels, such as pressure cookers and sterilizers, to indicate at what temperature and for how long material contained within the vessel has been heating or cooking, is disclosed. The indicator uses a material such as a thermochromic material which changes color at a predetermined temperature, and is constructed to provide readings around a 360.degree. angle. The indicator may, for example, be constructed as a knob on the lid of a pressure cooker or sterilizer or the link or may be attached to or as a replacement for an existing knob.

Abstract: A device for indicating the time integral of a monitored parameter comprising a strip of electrochromic material (2), e.g. tungsten trioxide, an electrode (3) at one end of the strip and an electrolyte (4) arranged so that, upon activation, electrons pass from the electrode (3) to the electrochromic material (2) causing the latter to change color so that a color change boundary (7) advances along the strip, the rate of advancement being determined by the supply of electrons between the electrode (3) and the color change boundary (7), which in turn is responsive to changes in the monitored parameter. The device may be used in the form of a self-powered cell needing no power source, as a time temperature indicator suitable for application to perishable commodities.

Abstract: An elongated body of molded plastics material has an end portion with longitudinally spaced and laterally extending temperature numbers overlying corresponding bands of liquid crystal compositions, and an elongated lens of transparent plastics material covers the numbers and compositions and is sealed to the end portion of the body around the compositions. In one embodiment, the compositions are carried by an aluminum strip or foil which has a center portion spaced within a cavity and opposite edge portions projecting to the outer surface of the body between the lens and the body end portion. In another embodiment, the body end portion has longitudinaly spaced cells or cavities for receiving the liquid crystal compositions in a slurry form, and in a further embodiment, the body is molded of a transparent plastics material and has an end portion which forms a second lens to provide a double-sided thermometer.

Abstract: The thermometer device enables the temperature of hot water or mixed hot and cold water to be read directly from the outlet of a tap or faucet or mixing tap or shower head. The thermometer device comprises a cylinder (1) including a conventional nozzle-type device (2) such as an anti-splash nozzle, a spray nozzle, an aerating nozzle, or a flow rate restricting nozzle. The outer circumference of the thermometer device is fitted with a liquid crystal temperature-sensitive sheet (3). This temperature-sensitive sheet is protected from ingress of water by a transparent resin envelope (4) which is sealed by a sealing ring (5). When water runs through the tap, its temperature is communicated to the temperature-sensitive sheet by conduction through the cylinder, and is then displayed thereon.

Abstract: A process monitoring heat history indicator in the form of a mixture of a first particulate component with a first characteristic color and a second particulate component with a second characteristic color. The first component includes a solvent system which melts at one or more defined temperatures so that when the mixture is heated to a selected temperature, it melts and wets the surface of the second component.

Abstract: A device for detecting the diversion of gas furnace or gas hot water heater exhaust into a dwelling due to chimney backdrafting detects a sustained rise in the temperature of the gases passing through the draft-diverter orifice. A significant rise in temperature indicates that the above condition has occurred. This temperature rise is recorded only after the condition has persisted for a sufficiently long period of time, thereby avoiding the recording of temporary backdrafting conditions which are not required to be recorded. The device consists of a high temperature resistant plastic strip or other material with similar conductivity and specific heat qualities with a temperature sensitive color-change material mounted on the surface of the plastic strip at one end of the strip. This strip is attached to the furnace or gas hot water heater in a preferred location with the color-change material facing away from the normal flow of backdrafting exhaust gases.

Abstract: A new process is described which is useful for producing novel articles of manufacture useful for monitoring the time-temperature history of perishable items. The process initially involves forming a solution comprised of a diacetylenic monomer and a solvent. The solution is frozen, and the frozen solution having crystalline diacetylenic monomer therein is irradiated to partially polymerize the diacetylenic monomer. Partial polymerization of the crystalline diacetylenic monomer admixed with frozen solvent results in the production of a novel article of manufacture having color. The novel article of manufacture is comprised of frozen solvent, diacetylenic monomer, and colored polydiacetylene. Due to the intensity of the color of the polydiacetylene, the entire article of manufacture appears to be colored.The colored article of manufacture may be attached to various perishables to monitor the shelf life of the perishables.

Abstract: A new reversible temperature indicating composition for use in temperature indicating instruments is diclosed which is capable of accurate temperature indication in a variety of colors and characterized by a minimum range of hysteresis so that the marking drawn in this composition can decolor at or close the temperature at which its coloring takes place. In addition, the composition can provide a wide variety of hues and can be readily prepared. These and other advantages are provided by the inclusion as a main ingredient of an ester compound having .DELTA.T value, defined .DELTA.T=melting point--clouding point, in the range under 3.degree. C., the value that determines a desirably small range of hysteresis.

Abstract: A thermochromic composition comprising (1) an electron-donating chromogenic material, (2) a 1,2,3-triazole compound, (3) a weakly basic, sparingly soluble azomethine or carboxylic acid primary amine salt, and (4) an alcohol, amide or ester serving as a solvent.

Abstract: A can container made of soft material such as aluminum having a wall thickness of less than 0.2 mm is used for low acid foods or drinks having pH of more than 5.0. A controlled quantity of liquified nitrogen is introduced into the can filled with the low acid foods or drinks and then the can is hermetically sealed off by double-seaming. The liquid nitrogen is soon gasified in the sealed can to increase internal pressure of the can to a level sufficient to prevent the can from being deformed. Then the can is subjected to retort sterilization treatment at a predetermined high steam temperature for a predetermined period of time for sterilization of any possible bacilli and bacteria in the low acid foods or drinks in the can. Prior to retort sterilization treatment, a thermal sensitive paint is applied to the can, which will change color when exposed to a steam of a predetermined temperature for a predetermined period.

Abstract: An aging gauge comprising a container having a fixed or a variable sized t opening with a cap which can be opened to control the sublimation rate of a thermally sublimational material contained within the container. In use, the aging gauge is stored with an item to determine total heat the item is subjected to and also the maximum temperature to which the item has been exposed. The aging gauge container contains a thermally sublimational material such as naphthalene or similar material which has a low sublimation rate over the temperature range from about 70.degree. F. to about 160.degree. F. The aging products determined by analyses of a like item aged along with the aging gauge for which the sublimation amount is determined is employed to establish a calibration curve for future aging evaluation. The aging gauge is provided with a means for determining the maximum temperature exposure (i.e., a thermally indicating material which gives an irreversible color change, Thermocolor pigment).